A guess, as a layman, would be BiPolar Disorder. High achievement interspersed with bizarre epsodes of incoherent behaviour, usually well controlled with medication. Unfortunately BP folk are not good with compliance/medication.
I am also guessing, but I believe FAA would not issue a Class I to someone with BPD I. If he was trying to maintain w/o meds, a breakdown was probably overdue. It is the damnedest thing, I had a dear friend with BPD. A super achiever, athlete, popular and quasi famous, especially within his profession.
Captain Osbon is Ill, not "bad". Let's be grownups, shall we?