I live with my grandparents and my uncle. I help out around the house with more of the physically demanding needs around the house so my grandparents do not. Recently my grandfather had a pacemaker installed in his chest and due to some health concerns the doctors told him he could not drive for about two months. He was with my other uncle in another state for the surgery and first month. He was extremely combative with my uncle (His third son) and came back home when things got pretty bad between the two. Now he is back home with me my grandmother and other uncle (His second son). I have been driving him to the places he needed to go and aside from some belly aching about my grandmother and uncle we have been fine. Mind you he gets into a number of arguements with my grandmother on a daily bases and has even come to blows with my uncle here. (Nothing serious, he is not physically capable to punch all that hard.) The number one arguement he has is that he wants the keys to the car to do random things around the house (that I generally take care of). We ask him to wait for the next day or morning for us to take him. He gets frustrated that we don't give him the keys to the vehicle and usually just shouts at us. Today he was working on the pool in the backyard while I was out with my son and friends. I came home after dropping my son off with his mother late in the evening. He came to my room asking for the car keys and exploded when I said the doctors hadn't cleared him yet to drive. He lunged for me, I assumed he thought he was going to push me aside and just take them. after a small struggle of trying to close they door on him he walked off screaming for me to get out of his house.
I'm not sure what to do with any of this. I'm extremely worried for him to be allowed to drive again because even before the pacemaker surgery he would narrowly avoid causing an accident (And I mean by luck rather than driving skill). He is borderline Dementia with constently losing the keys or wallet he was holding 5 minutes before. He has even called the police because he couldn't remember what dealership he took the vehicle too. It was lost for about a week when he called convinced they took off with his truck. When the dealership told the police they have been trying to call him to pick it up he played it off as it was their fault for not leaving a voicemail. (They did about twice a day. He just has no idea how to use his phone.)
I am already making plans to move out in the next year after finishing school, so I'm not worried about myself. I just don't know what I can do about him getting worse. Several of us in the family don't want him to drive but with his combative reactions mostly everyone has been throwing their hands in the air. But I'm certain that he will hurt someone if we just let him go do what he wants.
So your Grandfather wants to drive. Hmm. Very tricky. Does he remember the Doctor's driving ban? Does he understand it?
Has he had a dementia screening test by his Doctor? If not, try to get him there (for a 'checkup'). His reasoning may be worse than you suspect...
Either way, whether personality or cognitive impairment - if he or others will be endangered by his driving you will need to act.
Tell him no. Keep hiding the keys. Keep the message simple "Doctor needs to un-ban him".
My elderly uncle was driving when he shouldn't have been. He went through a red light and was t-boned, which killed his wife, a cancer survivor. Please remove the vehicle from the premises and tell him it's in the shop for a big repair and maybe he'll stop focusing on it. Arrange for others to take him places at regularly scheduled times so that he gets accustomed to others driving him. Have things delivered to the house to remove reasons to drive to shops. Keep reminding him of the driving ban from the doc.
His aggression is certainly a concern and just because he technically can't "hurt" anyone a facility might not accept someone with that level of aggression (they can swing an object at someone and still injure others). He needs to be assessed for possible medication to help with that, for his sake and for others.
FYI you can anonymously contact his state's DMV and report him as an unsafe driver. They will most likely send out a letter telling him to come in for a retest. Make sure no one takes him to that appointment. Allow his license to be revoked or expire. He will continue to stew about it but it would be unethical to not step in to prevent him from hurting others or himself. A vehicle is a multi-ton weapon to be used only by those with all their mental (and physical) faculties. And in this day in age of road ragers, he may provoke the ire of another sick driver (as my mother did and nearly got her elderly butt kicked on the roadside because her ability to reason was impaired). Wishing you much success in getting through this challenge!