You can report him to DVLA yourself...
My mum has told us to tell her when her driving becomes too bad. Luckily, she's still a good, safe driver at 76. That said, her car is on its last legs and she probably won't bother replacing it.
Hmm, easier said than done and should an 'in-law' start World War 3 in the family ?
My FIL couldn't drive a couple of years ago due to COPD and being on oxygen (hospitalised for a number of weeks), but my SIL was encouraging him to drive - he went out a few times to the shops with the oxygen canister in the car (he was supposed to notify the insurance - didn't). He is very stubborn, and as soon as one bump is repaired, he aquires another. The car is about 3 years old, and has had repairs to the following:- Front Door, rear door, front wing, rear wing, rear bumper x3 (has camera and reversing sensors), front bumper x 2, wing mirrors x2, rear light cluster. So far it's all parking related, but he really can't see properly. He loves blagging his medicals.
The issue is one sister is 'daddy's favourite, and she has a habbit of encouraging him to do things he shouldent, one sister is always 'on the fence' and my missus is the sensible one. Not easy.
He limits his drving to going to the supermarket these days.