How do I deal with my father who resents me helping my mother care for him?

Talk to your mom--how is she coping; she can make decisions regarding his care plan. If she cannot cope you may want to talk to a social worker to discuss what is available in your community.

ghostlyruby: Imho, more information is needed from you to make a valid response. Thanks in advance.

I would first like to know:

how father is showing his hostility (what is he doing)
what he needs help with (which tasks and routines)
what does the OP think his reasons might be? - while it's true that you can't "reason with dementia," the person still has reasons for his wishes and if you know what they are it can help you to reassure him.

But the OP seems to have vanished..?

Am I missing something in some of the responses? I don't see Ghostlyruby mentioning dad having Alzheimer's. I'm disturbed at some of the strongly worded responses. I don't see enough information for some of the 'advice' to be of help to her.
If her parents have been married a long time, dad may be of the mindset that he is true to their marriage vows of "in sickness and in health" and mom might feel the same. My thought is to try a gentle, non-threatening conversation when dad is calm and try to feel him out as to his resistance to her helping him.
A conversation with mom would shed more light on the situation as well. I found in years of doing home health nursing, one way I found to work was to share with dad, how so very tired mom is looking. "I'm so proud of what a great job you do caring for mom". "I'm so worried about her, are you"? "Is there some way that we could find a solution"? "I'm selfish, dad, I want BOTH of you around for a long time".
Best of luck

First, see if medication can calm him down. What specifically is his reason for objecting to you helping him? Does he realize she has medical issues and is limited? I would sit him down, with other family if you have any. I would explain in no uncertain terms the damage his hostility is causing and you simply will no longer tolerate it and he will from now on have to accept and follow boundaries and rules. Tell him if he does not cooperate, you will do everything in your power to move both of them into a home. What he is doing is wrong and causing great suffering. In the meantime start looking for outside options or a caretaker. You have to do whatever you need to do, without limits, to stop his hostility. And if he is treating you badly, find ways to eliminate him from your presence before he destroys you. But it will be tough and YOU must become the boss.

Daddy struggled when mother would leave to go anywhere--and since she was his primary CG, this made it hard for her to leave him with anyone. He had to know, constantly, where she was and when she'd be back. This is in the days before everyone and their dog had a cell phone, so mother would call on a payphone every 1/2 hr or so and remind him she was OK and would be home soon.

I don't think we ever effectively made him feel TRULY 'safe'. After a checkup with his doc he prescribed some topical Valium and we would rub that on his inner arm. Then wait a bit while mother got ready to leave and by the time she left, he was calm and able to stay so for several hours. Whomever was caring for him had to be interactive and keep him occupied or he'd start 'worrying'.

He was better with some people than with others. That's normal, too. I could stay for hours and he'd be OK, but OB made him so anxious and nervous, he was never allowed to 'tend'.

It was CRUCIAL that mother get a break now and then. She looked forward to simply leaving and going to lunch, puddling through a store or just running her various errands without constantly having to call to check in.

Had we had cell phones, I know it would have calmed dad to know at every given second that he could call mom.

Sadly, with dementia, not a lot of what you say stays with a person. I think for us, the valium helped the most.

You and mom let him know what your mom isn't willing or capable of doing and if he can do those things by himself then that's great if not then make List of things that he or your mom can't do and then asks if he wants them done if not don't do them or let him know his only options of the thi gs he can't do or your mom is
1. Not getting them done.
2. Having you do it.
3. Hiring a Caregiver.

He might feel more comfortable with a male aide. There may be an embarrassment factor with you helping him.

Often with dementia there is 1 person that they will "cling to" or "shadow" this is their Safe Person. The one they can trust and that is there for them no matter what. Most often it is a spouse. If you have recently moved back you are not yet a "safe person" for your dad. Give him time and he will begin to trust you more.
The other important thing here is ...is dad aware that you are his daughter? If so he may feel very uncomfortable if you are providing imamate tasks like changing, cleaning, bathing and dressing. If this is the case he will relax a bit as he gets used to you helping but in the mean time if you can talk to him and distract him with general conversation while helping him it may take his mind off what you are doing.
When you start helping him if he says he wants "Ruth" to do it just say he is at the store or went to get the mail or a walk.

Your father is probably depressed and frustrated. Take him to a doctor. He might need to be on medication for anxiety or depression. My mom was having angry outbursts and this is what we did. Her mood improved greatly. Don't allow your Dad to place unreasonable demands on you or your Mom. Your mom needs your help and shouldn't have to sacrifice her health. If the hostility continues tell him that he has two choices: either accept help from you or outside agencies or placement in a retirement home or assisted living facility. Tell him that you are doing your best and that you would like him to accept help gracefully. Contact Community Care Access Centre and have them come out and access the situation. The most important thing is your parents' health and safety. Do what is right for your mom. Your Dad may or may not adjust but that is secondary to your Mom getting the help she needs. Good luck to all of you.

I think this is a "normal " behavior to want your loved one or primary caregiver all the time. My 92 yo mother, who does not have Alzheimers, always wants to know where my brother is. He lives with her and she knows without him she could not live at home.
My sister and I visit and assist her weekly. She also has 3 wonderful caregivers.
So when she asks about my brother, I think she just wants assurance that he's around and her living situation won't change.
Perhaps, if you tell him, "Mom is tired and resting, she's asked me to ..." I am sure that you will need to repeat many times. Perhaps, changing the topic might help.
Best wishes to you and don't take his resentment personally.

Does he have dementia? I would let him know that your mom is not feeling well and she asked you to help her.  Let him know that you love him and want to help when she needs help with him.  Some men have pride and don't want their children helping.  I did more things for my father and saw things I thought I would never ever see and luckily it didn't bother him.  he also had dementia.  I guess it depends on the person themselves how they see things.  I hope someone else has better information. wishing you luck.

Very diificult situations congrats on caring TOO many other people would not care YOU DO!!!!!! Next take a deep breath 3-5 of them and count to 10 million, just kidding. I suggest that you speak privately with your mother & ask her HOW YOU CAN HELP HER WITH DAD! Then let her present this to dad THAT SHE needs your help NOT HIM!

Dip. Leave. Exit.

What's that saying about not negotiating with terrorists?

My Mother only wanted Dad to help her. Even when he would be in hospital & post surgery! "I don't need other people to help me. He can do it." Yes you do need other people. No he can't do it.

Like your Father, they are focused on what they WANT & will deny, or cannot see, what they NEED.

You can be sympathetic to his wants, Yes Dad, Mom is helping you. So am I. So is (insert Aide's name). We are all in your team.

But organise the care he needs before your Mother's health is destroyed.

Because your father has Alzheimer's, he will be nearly impossible to reason with, as you already know. You can try explaining that if he doesn't let you help your mom, that you will have to hire outside help to come in and assist your mom, as she just can't do it herself anymore. But realistically, he probably won't understand all of that, and if he does, he won't remember it, so you just have to do what's best for him and your mom right now. Have you tried bringing someone else in to help, to see what his reaction is to them? If not, you may want to try that, just to see if he responds differently to them, than he does to you. And if he does respond more positively to the outside help, then you have your answer. And if the response is the same as with you, then you know it's not you, it's just him and if you chose to continue to help mom, then you'll just have to make the best of it.(if you choose to keep him at home) Or you and mom have the choice to start looking now for the appropriate facility for him to placed in, as things with your father, as you already know, will only continue to get worse, and with your mom's health issues, will just get to be too much for all involved. Wishing you the best.

Arrange to get a needs assessment done for both Mum and Dad. This will make it clear to you and Mum what is needed. What Mum is capable of providing and what others will have to provide.

Once you have this information, you can tell Dad that he has 2 choices, accept care from you and perhaps hired caregivers, or residential care. Make it clear that Mum cannot and will not provide all his care.

Now you have stated Dad has dementia, so he likely will have to be told over and over again.

Is it possible for Mum to go away for a few days for Respite? If she is in the house, Dad will demand that she attend to him.