I need advice. Should I talk to mom about what happened?

I agree with lealonnie1, and maybe you should consider contacting those relatives to give them a heads-up just in case your mom talks about it to them or other family members. You don't have to go into specifics, but maybe something along the lines of, "The anesthesia and prescription pain meds caused a temporary cognitive side effect so if Mom says anything that doesn't make sense, it's probably that, but she's getting better."

Just give it time; don't talk to her about anything right now as the hospital delirium tends to stick around until the elder is out of the hospital and rehab, if she's going there for a few weeks. There's no point in talking about anything that matters b/c she's likely not to remember it anyway. Wait until she's back home and then see if she's still convinced her DIL and GD did something awful to her; THEN sit her down & have the conversation with her that those things did not really happen & were just a bad dream. I'd be surprised if she doesn't forget all about it, truthfully, once she's back home in her normal environment.

My mother had the same issues when she was hospitalized with pneumonia for a week and then went to rehab for 3 weeks afterward. The hospital delirium was off the charts and awful to witness. After getting released from rehab, she got back to her old self in pretty short order.

Wishing both of you the best of luck moving forward.

I would wait until she has more clear days than not.
But if she mentions it and gets upset I would address it sooner.
I would tell her that it was the medication that made her see, hear things.
Please tell daughter-in-law and granddaughter about the delusion and that they should not be upset and if it means keeping the peace and making things better, easier they may need to “apologize” to make mom feel better. This is one time when pick your battles may be important to soothe mom

I agree with the others and just give this time -- a lot of it.

I was (relatively) young and healthy when I had back surgery at age 46, and I swear, my brain didn't work properly for a solid month after that anesthesia. (And it made me lose a ton of hair to boot!)

An older person will take much longer to bounce back, so just wait it out, warn the DIL and granddaughter what's going on, and play it by ear.

NewandTrying
Just chiming in to say my mom went through the same thing. It was horrible yet fascinating at the things she came up with and had absolutely no memory of later.
She did remember that she had a bad reaction but not the specifics. My mom did not have dementia.

My aunt, who has dementia, in early days, would latch onto a false memory and want to share it with everyone. I decided to ignore her comments when she did this with one story in particular and discouraged her from sharing it with others. My idea was that the retelling was reinforcing it in her memory. She finally quit telling it on a daily basis but it was so real to her that every once in awhile she will start to bring it up and stop if I’m in the room.
Why she can remember a false memory but not something from her real life is such a conundrum. I know this isn’t hospital delirium but just wanted to mention she might be reinforcing her experience by retelling it.

I’m sorry your going through this.

After my moms stroke she was not really alert for 2 months.
Mix stroke recovery and healing with new medications - UTIs and the trauma she endured - she had so many weird things she would say.

It took her time to go through them and place them or make resolve with them. She now works with neuropsychologist for talk therapy. He is explaining a lot to her so she can learn more about her injury and what the brain can do and it is also helping me.

You can request one while in the hospital come Eval and maybe can help guide you going forward. When mom did have severe delirium once - a neuropsychiatrist did follow her case and stop and check in throughout her stay - so maybe request to speak with them. Best wishes

Without the trauma of a broken hip, hospitalization, or surgery, my hubby decided my cousin stole his mom's turkey platter last Thanksgiving. Even though we've shown him the platter numerous times he still believes it.
Not knowing this, when my sister stayed with him while I went on a quilting retreat, she invited my cousin come over. For 2 weeks after I got back, he went around looking for all the other things she stole. I'm dreading this Thanksgiving.

I think you need to play a wait and see game - perhaps asking those she has the delusion with to stay away for a few weeks (it is no doubt a lot easier to explain to them than it is to her).
Hospital delirium can last days, weeks, months or even be permanent so I think your 2 days is a very short period to expect total recovery even if this is going to happen. Try being patient for a while and assuming she will improve. If she does then she will lose this delusion anyway (or you will be able to talk about it sensibly with her), id she doesn't then I doubt you are going to be able to discuss it logically and making an decision on how the daughter - in - law and granddaughter and going to handle seeing her or not going forward is better had with them. Best wishes for hopefully a not too long recovery.

My mom had a few of these episodes where she would tell me something that seemed like they were delusions. In one case, she told me that my Dad's minister came to pick her up for a luncheon at a friend's house (this was supposed to happen) and when they got there, it was too icy to get out of the car. When the minister brought her home, she told my Mom that she didn't visit her more often because Mom was Catholic and the minister said this in a very mean way. I couldn't believe this happened and didn't know what to do. Mom continued to bring it up for months which really made me wonder. It clearly upset her but I wasn't ready to confront the minister because I didn't know if it was true! I finally suggested that maybe it was a dream that seemed very real. Over time, if she started to tell me about it again, she would say it probably was a dream and would move on. About a year later, we saw the minister at a funeral and I made a point of bringing Mom over to talk to her - all seemed OK - no hint of the "incident" and Mom didn't bring it up again.

Another time, when Mom was in MC, she was frantic because she said one of the other residents kept coming in her room. I could believe this but then she said this resident would go through Mom's stuff and ended up putting her things in Mom's closet. I looked but didn't see anything so I guessed this was another delusion. Well - when Mom had to move to another facility and I cleaned her things out - guess what? I found a bag of this woman's things - stuffed in the back of the closet! From then on, I would look into the things she said and address them if it was needed. Sometimes, they were true (or at least partly true) and I didn't want to chance dismissing something that was upsetting to her.

To avoid a rift in the family, speak with the folks your mother believes harmed her so they know she was not coherent at the time and may not be able to release that false impression due to the medication-induced delirium. As your mother recovers from that bout of delirium, try to help her understand the medication confused her brain; engage her doctor to explain what happened to her. Depending on your mom's level of understanding, you can tailor the explanation, maybe even something as simple as "You had a temporary bout of confusion from the drug combination that gave you something like a bad dream that is not true. These people love you and would never behave that way."

When my mom took her last fall, that led to her last days, she was found having been on her kitchen floor overnight, near hypothermia. She was hallucinating that 'workmen' were in her house, possibly the EMTs that found her; the idea stuck with her for a long time but she eventually reframed it as a 'bad dream', not real. I didn't argue with her, but let her come to her better understanding.