First, wife said Dad had Alzheimer's and that she couldn't leave him home alone anymore because he would wander off or let just anyone into the house. While his wife was at work, he would come to my apartment every Sunday and stay for about 6-8 hours each time. Each time he came over he had to ask me where the bathroom was located. Then he was put in adult daycare, and in Jan 2017 he was diagnosed with Parkinson's. Does that sound like someone competent enough to enter into contracts?
And, I know from experience that even small apartments can be confusing. Doorways, and maybe a hallway with more doors. If I have “to go”, at my age, I want to know exactly which door to open. Short term memory loss doesn’t mean incompetence.
If you think he needs protection from entering into contracts, you might ask his doctor to evaluate his competency. Most doctors have forms for that. It might be a useful document to have if he enters into a contract that the family is concerned he may not have fully understood.
What does it have to do with a settlement from the VA, you said no money down.
Do you have proof that he was under duress when he signed?
Just because someone is 88 doesn't mean that they wouldn't enjoy a new home and most men want to provide for their wife in the event they pass first.