How do I get power of attorney for my dad?

You say ur father is in a nursing home and has ALZ/Dementia. If in a NH his Dementia is probably progressed to the point he cannot assign u POA. You also say "from sister" meaning she has POA. Your only option is guardianship which is very expensive. Medicaid will allow u to use Dads money if u think u will need it in the future.

Ditto to what WorriedinCali posted. If your dad has full mental capacity he is totally able to make you his durable PoA without permission, input or knowledge from your sister. If there is a power struggle between you and your sister, it would be advised to have this done through an attorney, with a letter of competency from his doc. Then your sister can't easily contest his mental state when he signs a new PoA.

You have to go to court in order to obtain guardianship. It can be a long expensive process. Your dad has Alzheimer’s or dementia? If he’s still mentally competent then he can still assign a POA. You can either get the forms online or see an attorney if finances allow for it. You may want to get something in writing from dads doctor stating he’s still competent in case there is an issue with your sister.