Flying is not a right, public service, or charity.... I have no knowledge of the particulars of this situation so won't comment on it specifically but not every person out there can be accommodated. Unpredictable behavior and inability to follow instructions are the reasons we don't allow intoxicated or "overmedicated" people to fly.... Mental illness, developmentally disabled, or just plain crazy folks can present unique dangers to other passengers or themselves in a crowded cabin. There are other options available...

And yes I do have Autism experience in the family.