When mom got to the point where we had to look after all her finances, we closed all the various banks accounts and moved everything into one bank account where we banked. With the power of attorney activated, we put the bank account in mom's name, with ourselves (two of us) and mom as signers on the account. That way we could pay her bills - at least those that didn't come out of the account on auto-payment withdrawals, and her pension cheques could be deposited directly to the account. At that point, mom was still capable of signing a cheque, though she couldn't write one properly herself. We'd write the cheque, show her the bill it was for, and explain it all to her, then she'd sign it. I don't know how many times we'd sit down with mom and the monthly bank statement when it came and go through it with her again, explaining what each cheque we'd written (and she'd signed) was for, and what the deposits were, and showing her how much was still in the account.
Part of the problem with this was that she'd really lost the ability to understand what we were explaining, and even when she appeared to understand it, that understanding would last for a very short time. A few minutes, or half an hour later she'd ask all over again. Even though we knew that we were fighting a losing battle, we still felt compelled to try and explain it to her whenever she asked. I guess part of that was simply because we wanted her to understand, and part of it was because we felt strange handling her finances, and trying to make decisions we felt she (or dad) would have made themselves.
To make the major part of her money work for her, we'd put some into an investment fund - one that guaranteed the initial investment amount would never decrease, but that she'd earn a pretty good amount in interest. There were other funds that would have earned her more, but didn't safeguard the initial investment. It isn't easy to make financial decisions on someone's behalf, and mom really didn't understand the investment fund, even when explained to her in the simplest way. The only thing she cared about was having enough money to pay everything. So it seemed the simplest thing to do was explain that this ensured she'd have more money than she'd she ever spend. That was enough to make her happy.
At least until she sifted through the multitude of riff-raff in her handbag and pulled out this old bank book. For probably the hundredth time I tried to tell her that this bank account was closed - gone for good. The money had been transferred to her new bank account, with all the money from all her accounts, and once again showed her the balance. Which was more than healthy.
One thing she did seem remember was having a bank debit card. She'd never really understood how to use it, not from the time she first got it, but she did understand that the card meant she could get money out of her bank account. After her mind started sliding, she still knew a bank card meant money, but didn't understand which card was a bank card. From her wallet, we had removed bank and credit cards, and left her with a variety of others - her health card, her (now defunct) driver's license, her social insurance card, birth certificate, and a number of other (somewhat useless) cards. Many times she'd produce one of these cards and ask my daughter to get her some money.
By this point, I was mostly running on empty and doing things on "auto" mode. I needed a rest. My sister took mom home for a week. And all hell broke loose.