First, I don't think AOPA is able to do much more than write their own press releases. The Federal Government is big, slow, and quite monolithic. It take more than what they've got to institute real change. They might like to crow about the whole medical reform thing, but I think the real driver there is the a guy who landed on a closed runway.
As far as ADHD and autism diagnoses, we know more about the latter these days. No one really talked about a spectrum of anything back in the day. But they were there, they were always there. We didn't joke about the short bus for nothing. I suspect that lots of kids who act out for all kinds of different reasons get the ADHD label and some nice drugs. Easy way to deal with the problem. Some of them might even be ADHD. But I can't blame the parents for listening to the harried doc or nurse and not think ahead 20 years to whether their kid might want to fly airplanes. Back then folks listened to medical professionals more than now, I suspect. Of course, these days we're all conditioned to get a diagnosis and some pills.
By the way, your own friendly neighborhood Steingar was so diagnosed when he was a young pup. The whole middle of the Bell curve is all too real, at least it was in the day. Hard to believe anything that popular would go away in the interim, though. Boosted a grade solved the problem quite nicely (my Pharmacist father though medication was BS), though it created an unintended consequence. Never a physical giant, your protagonist was tiny compared to many of his colleagues, who reminded him of it both often and brutally. Then again, that was a huge assist in establishing studious habits and a rapier wit (if I do say so myself), both of which have assisted yours truly immeasurably in the years since.