Mary
Remember I am an ATP with a current type rating so have to be tested every year in the sim.
Take my word everything is thrown at you in the sim and any signs of dementia or slowing up would show up!
i also fly a multi crew jet with another commercial pilot as an FO.
Part of that relationship is monitoring i.e. the younger FO is checking all that I do and visa versa
There was a well documented airline crash where the Captain was out of the cockpit and his YOUNG co pilot failed to identify a stall and took the wrong actions but this was a young guy not some demented old relic.
Here you get onto my pet subject which is the modern training directed at recovery from anything at the incipient stage and the churning out of aircraft drivers rather than handling pilots but we have done that one to death
But I find it hard to understand why you want 60 year old pilots to chuck in the towel when you yourself were still instructing at 77 years of age? That I admire!
I would be all for pilots over 70 having special flight tests every 6 months or a year to check they are up to speed especially regarding reactions and ability to pick up their game under pressure.
Pace