My father gave his mother POA and the day after she went and signed his portion of his dad's land and everything he left to him over to his sisters. Is there any way that can be overturned or pursued to get back? He didn't tell her to do it or anything. That was her decision and she felt like she had the rights.
Sounds very fishy and manipulative on grandma's part.
Was the POA drawn up by a lawyer, witnessed and notarized? If not, then she didn't have legal POA. And there r two. One for financial and one for medical. You need to find out what lawyer allowed this. Land changing hands has to be filed with the County Clerks office for tax purposes. Sounds fishy to me too.
He could ask her to handle business for him with the POA, but she can not decide to do anything on her own, unless the above is the case.
What is your dads status? That will help get you better answers. The more information that you provide the better the help. No personal information required, just info like dad is in a coma or he was preparing his documents because he has a terminal illness, he has a brain injury, you get what I mean.
This will also help you get information on how to help your dad get his property back.
Each state operates a little differently, so with the info you have provided I would say to talk to an attorney, they can help you understand how your state works and if there is any legal recourse. A lot of attorneys will give you a free consultation with the hopes that you will hire them to represent you and dad.