Of course, you mentioned this to pro-standards or the fitness for duty committee right? Did you raise your concerns with the pilot? Or did you just come on FI.com and throw ALL the "seasoned" pilots under the bus because ONE GUY didn't perform well?
I'm tired of bashing the older guys. This is, and should be, handled on a case by case basis.
I'm 36 years old, had a 67 year old sim-partner who didn't perform well in my last recurrent, and handled it through the proper channels which began with a heart to heart with him.
Hopefully, we'll all be 67 someday, and who knows what our situation will be by then. By that time, I will have had 41 years with my company (God willing) and will NEVER judge why a pilot decides to work or retire.
In short, did you ever consider that YOU may NEED to work when you're 70? Something to think about.