My dad had dementia and got lost on his way to, and from, the barber shop, so my mother confiiscated his keys. That happened in Prescott AZ, so I was back East, and never had to get involved. This was about 2000, near as I remember. From what I heard he was pissed at first, but soon got used to my mother doing all the driving. Dad was about 85 when he started showing major signs of dimentia, so my mother was the decision maker of when he quit driving.
My mother drove until she was 96, 2017, and just decided she was going to stop driving on her own, so I again, dodged a bullet. I had ridden with her previously to the time she decided on her own, and I never felt she was a poor driver. When she told me she had decided to stop driving, she did make the comment that she was surprised I hadn't tried to get her to stop sooner, but having ridden with her, she was a better driver than the majority of drivers currently posessing drivers licenses............
She was still able to get a renewal from AZ, so evidently they weren't concerned.
My father passed at 92, in 2007, due to complications from dimentia, my mother passed in 2020 due to a type of leukemia that affects the bone marrow's ability to produce white, and red blood cells. Her cognitive abilities were good until the leukemia started to have an effect, she was 2 1/2 months past her 99th birthday when she passed.
It all hinges on how well your body ages, and how long your health is good, everyone is different. Everyones reactions slow down as they age, and you have to be able to drive defensively to compensate for this. Currently I'm 71, and know my reactions have slowed some, but I also drive differently to allow for that. I guess if you can gauge how much your reactions have slowed, you can for a time make allowances to still be a safe driver. If you're unwilling to make allowances, you're denying that you've aged, and can be considered a hazard while driving.
To the OP, make a deal for the parent to get retested by the state, if the state passes the elder parent, you'll shut up about the issue. If the state says they're not competent, then they're the bad guys, not the children. If they're as sure that they'll pass the test, they may take you up on the offer. If they're as bad as you say, they won't have a snowballs chance in hell of passing. The state has the say so for new drivers to make sure they're competent before issuing a license, they should also have the duty to make sure elder drivers are still competent while driving.
Most people view driving as a right, but I learned long ago that it's a cherished priveledge, that can be taken away for various reasons. Rights, and priveledges aren't the same, and priviledges are only allowed, until they're abused, or the person can't meet the demands placed upon having the priviledge.
Rights should be granted to a person until they die, or a legally deemed unable to understand their rights, then the persons rights are transferred to a care giver. Priviledges can be denied when the person can no longer sustain the conditions placed upon the priviledge., there's a difference.
