Is it legal to use POA to remove a spouse from home title then set up quit claim deed for girlfriend's son?

My father is still legally married to my mother. They both have dementia but mom's is more advanced. Just learned that my father removed mom from the title of the family home and set up a quit claim deed to leave it to girlfriend's son. I am on the POA if dad is "unwilling or unable" and have been taking care of mom's medical needs for about 7 years. Mom was in better shape then and signed a health care surrogate for me to help her. She always hoped dad would come back and never wanted to pull back the POA. But the girlfriend has been widowed three times and now her family will have our parent's home which is not how mom would have wanted things to end up. I would like to move to Texas from Florida to be near grandkids and without the full POA it will be tough to move mom and make sure she has the care she needs. Not sure what options are available to get answers.