The flooding in PA was a blessing in a way. Dad's home and car was damaged beyond repair and we were able to my parents into a personal care home. I did have the doctor revoke his license, however, because all he talked about was getting another car. Now, they are in the secure dementia ward, but if he got out he'd probably call a cab and go straight to a car dealer/rental place.
His dementia is so bad that he got lost a block from his house before (not just once) and got lost coming to my house recently.
He's upset - and I understand it is an ego blow - but he's safe. He wants to appeal, however.
In PA, a doctor can write in to the dmv and have a license revoked. If you can get him to the doc for a "physical" tell the doc to do a cognitive screening.
If that doc won't send in the proper form and revoke his license, find one that will. It took years of trying to get Dad's family doc to do it, and finally the doc at the home they are in had it done in 2 weeks.
Not easy to do - but necessary when the person has health issues that make driving errors more apt to happen.
Call the doc today - he or she can help you. Good luck. I can sympathize!!