As an older pilot myself (68), I have some concern whether I'll be able to decide when I've had enough. So far, my medicals, my BFRs (that dates me, doesn't it?), and my IPCs say I'm still OK. The only thing I seem to forget--and that's almost every time--is to shut off my ANR headset at the end of a flight, but it has an auto-shut off feature, so that's not too bad.
I have also been told by ATC that I'm somewhat off the centerline when I think I'm on it, but I've never argued about it--just corrected as ATC advised--at the time, my VOR head was original equipment in a 49 year old airplane, so I assumed it was in error. But I have heard obviously older pilots on the radio get into similar arguments with ATC. I listened to a really long rant one day when an older pilot (he bragged about flying for almost 50 years) complained to Denver Approach about being diverted around the Denver B instead of through it, launching into a harangue about the extra cost of fuel and time and wear and tear on his airplane, etc., etc. I think he tied up the frequency for almost as long as it took him to fly around the B.
Getting older entitles us to be curmudgeons, but it doesn't entitle us to fly when we're no longer safe to fly. Perhaps this guy has reached that point.
Cary