Question about a deed

My father currently has his name only on the deed to the house my mother and he live in. He also has his name only on property given to him by his mother next door when she died. He and my mother have been married 57 years this year, but her name is not on either deed. My father has dementia and my mother is ill right now and they are currently staying with me. They currently have a loan against the property as well. I currently have durable power of attorney for the both of them but I don't know what to do. My concern is if I need to sell the house and property to pay off the loan, can I do that without my name being on the deed? I'm trying to determine the best course of action. Please help.