Stepfather With alzheimer's

[Handler]

My question is if my stepsister was wrong and can what she did be made right. My mother(86) broke her hip and was in rehab. Our stepfather(94) has Alzheimer's and was home alone. We asked his daughter to help care for him. Now to fill you in she hasn't been in his life for close to 20yrs. No cards letters or calls. So my sister and I have been the ones caring for mother and stepdad. Now we needed help and what she did was amazing ! On Dec.21 she took stepdad to the bank had him sign power of att. over to her (had been mother) and she took $41,000.00 out of their joint acc. and opend another acc.. Stepfather can't write a check on it without her permission ! What was left in the joint acc. was minimal at best . Mother found out about this when she came home from rehab and went to the bank to see the balance so she could pay off her hospital bill. Needless to say she is devastated ! Stepdad doesn't remember signing anything and when he remembers what has happened he is very angery. Can stepsister be made to put the money back and can mother get power of att. back in her name ?
My sister and I have never wanted to know what they had in the bank . My sister paid bills for them while mother was in rehab.. Mother would sign a check my sister would make the chek out to the company that was owed then mail it. We never got into their money didn't want too as it isn't our buisness! When the time comes we will do what needs to be done but until then we are not going to medal in their buisness.
Please help us to find out what to do for mother and stepdad.
Thanks,
Handler