Any tips for protecting finances?

Another thought:   can you access his account to monitor it regularly?   I would suggest a separate account, but sometimes spammers hack correspondent accounts and that's spread to yours.   That's happened to me more than a few times.   One relative has a practice of forwarding e-mails with collected photos or whatever.  Whenever I see "fwd. fwd....." in the title, I delete the e-mail w/o opening.   I got tired of screening out her junk mail and who knows what might be tagging along on it.

Specialka,

1.   Protective software.   

I had to get Norton Lifelock when Comcast decided not to provide it, and I couldn't get the updated CD of Norton software to load.  When I called Norton, it was either get Lifelock or find another Internet software company.  At that time, I wasn't interested in spending the money on another company with which I wasn't familiar (including the other well known company, the name of which I can't remember.)

From what I can tell, all Norton does that I know about is send e-mail notifications of how great it is.  It does NOT provide credit reports, or updates, or anything other than self aggrandizements and notices of how many "trackers" I have.   There is no way to verify that it's doing anything.

What I did though after my father died was contact one of the 3 credit bureaus and put fraud alerts on both of our credit files.  

2.   Spam Mail.

Over the years I've gotten my share of spam e-mail, but have always forwarded it (including the hidden data that provide more detailed source information) to my ISP and let it handle the spammers.   When Jobs was still alive, MS provided a better method of doing this, and I could also e-mail the scammer's service provider directly.  Now I let Comcast take care of it.  

It doesn't discern as easily as a human being though; it keeps blocking e-mails from someone here on the forum, allocating them to the "spam" file.   I just move them. 

3.   Protection.

The main protection is just not respond to any e-mail from ANY unknown person or company, especially ones (and phone calls) allegedly from Amazon, MS, and now phone companies.   

a.  Offline data storage. 

These threats, not to mention using electricity to handle finances, is one of the reasons I refuse to consider online financial activities.   I have done it a few times for bills and gifts for my niece's children, but I created a password protected document with all the data necessary:  name, address, phone, account number, etc.   It's stored offline on a removable hard drive.  

This allows me to transact but w/o specifically writing out account numbers, although I've found that the local township and city usually require some typing  of personal information, but I only pay online if I can't get to the office and pay personally, or just mail a check.

b.    Special account, only for spam.

One thing you can do is create another e-mail account just for the banking and bills, gradually move all other correspondents (friends and family) to that account, and let the existing one lie fallow.   Eventually if it gets too many spammers, close it and leave it closed before opening any replacement account.

The goal is to isolate the spam by creating a new account for acceptable mail, then delete the spam account, or just leave it as a garbage collection account.

Mac and Geaton are correct. Your father is lucky in that he is still functioning while realizing his diagnosis and its inevitability. My brother was diagnosed with probable early Lewy's Dementia. He put all bill paying in my hands with a POA, all banking, and he made me the Trustee of his Trust. He improved after this was done, and after he moved into ALF and sold his last small home by his own choice. He said it was the lack of worry. I provided him a full monthly written update of all assets in and all payments out which he kept in a notebook. We discussed how to invest any monies or CDs that came due, and who should be the beneficiary when this work needed to be done. We were able to sit and speak about his symptoms and he was a marvel at how someone can see the world so differently. He knew he was failing in that he would occ. call me and say "Hon, I know you will tell me that everything is all right, but I just got this call from Social Security, or someone who says they are Social Security, and they are telling me they can't deposit my money unless they give me.....blah blah". I would reassure him.
My brother died of sepsis before he could deteriorate further into the world of Lewy's. It is what he hoped for, and it is what happened.
You and your Dad need to be aware that there are monsters out there just waiting to prey upon him. He is still able to recognize reality and to make plans with a lawyer. Iron clad air tight documents that will allow the most willing and the most able in the family to handle his affairs for his absolute protection. You don't have time to spare. Please speak with him. Please do all you can to protect him, because they are everywhere. Yesterday even our CPA got hacked. We got a message supposedly from him saying "Alvadeer, can you help me" and when I replied the message said "I am laid up with an accident. Can you purchase gamecards in the amount of blah blah blah"....... When we called our CPA (also a friend) he said he didn't even reply. He only clicked a link sent to him. And now hacked and spending his days calling clients to warn them that's the case.
Ways to rob our elders is earning scamsters billions. They will become only more sophisticated. I wish you the very best.

I agree with MACinCT to get him to agree to add yourself as joint on his account and then open up online access to monitor his finances. Put most of his money in a savings account and enough in the checking account to cover bills. The challenge of dementia is that you can't ever know when he will have a lapse in judgment and give out his SSN or CC number and it just takes once. Just this week at 11:30pm I started getting texts from CapOne Visa saying here's the verification code you requested (I didn't), then charge alerts started coming in and I was able to lock my account immediately (not that I would be liable for any of those charges) but you'd know if your Dad was buying weird stuff or spending out of control. So I'd also open up online access for his cc if he has one (but don't become joint on it, just monitor his account).