It is very sad, but I think it is time for you or some other close family member to tell your dad/granddad/uncle/(
insert family relationship here) that it is time for him to stop driving before he causes a very serious accident! Yes, he will lose his independence, but at least nobody need lose a leg or even a life ...
He was joining the main road from a side road near a roundabout to his right. He was so 'target-fixated' on the exit from the roundabout that he forgot to look left as he pulled out into the space that I was about to occupy, forcing me to swerve left into the other lane in which several cars were bearing down on the roundabout.
Fortunately,
THOSE drivers had their wits about them and braked enough for me to get round his car and back into my lane again. I bellowed at him so loudly that pedestrians 100 metres away stopped dead in their tracks but he remained blissfully unaware of what he had just done. I looked back at him and he was still staring at the other side of the roundabout ...