It is obvious that pilots need to retire from active flying at part 121 airlines at the age of 60. The majority of the people that I've known over the years have been WAY wacky-the vast majority have been unable for an FAA medical, even if they didn't want one.
But several +60 people that I've flown with were REALLY REALLY gone not just in a physical sense, but in a mental situation. I had one guy start to preach to me in my hotel room after we flew to Hong Kong. He had his bible out and everything- he kept quoting his CRAP to me until I finally shut the DOOR on him. I refused to fly with him, but he was one of the people that wanted to be a Captain again!
Listen: I'd work with the guy. But the first time the religion reared its' ugly head...I'd walk out the door. That includes half-way across the Atlantic. This bastard could land the airplane by himself, as far as I was concerned!
I suspect that +60 people are a MESS. A few will test normal, but the vast majority really aren't fit to work at Taco Bell. Why are they considered for flying duty at Fedex and a few others?