How can I stop my mom from getting another ATM card?

Can't you as POA go to the bank and close out her account and open a new one? Or transfer most of the money into a savings account so that the ATM card will not let your sister take out more then just a piddly amount?

Removing money from the account sounds like a good idea to me. Transfer all but a small amount into savings, and move it back when you pay bills online.

I take it that the ATM card is only a problem if it is in Sister's hands. If mom gets a new one, ask her to give it to your for safekeeping. The way I convinced my husband to let me keep all cards was to say he shouldn't carry them to guard against identity theft.

Or, as DPOA, change the PIN number on the card.

Lots of ways to keep Sister from unauthorized use. Just do something quickly. Surely Mom cannot afford that kind of drain on her account!

I pay all my mother-in-law's bills online. I can transfer money out of her savings and into her checking when it's needed to pay her bills. However when her CD comes mature I do have to visit the bank and move money into her savings or checking. Otherwise, it's all online.

Thanks for all the helpful answers!