Okay, I may be wrong here (it's been known to happen), but this started when Barron failed a drug test?
IF that is how it started, then this is all on Doug. I quit playing in large part due to constant migraines in the last few years of my career.
I had them my whole life, but it seemed that after my wrist surgery, the frequency ramped up to almost daily. I walked away after 2 years of trying anything and everything (it seemed) to get rid of them. There was no drug testing then, and I tried all manners of mediations at the direction of my neurologist. A couple of years later, I had a student who suffered with migraines managed with propanolol, a banned substance (beta blocker). I too tried propanolol for 2 months when I was playing, and it had no effect on my migraines, but for this kid it kept them in check.
The Tour sent pretty specific guidelines, including the rules for appealing to the Tour for the use of prescribed medications. There have been a few players dealing with this process, including S. Micheel, who has a low testosterone disorder. He has had to jump through ridiculous hoops (IMO) to be able to use the medicine that helped save his career.
If I decided to try to play again, I would very easily know the requirements for submitting all of my medications. I do not agree with everything they are doing with this, but if what I understand is correct, Doug was taking a medication that was banned, and it is his responsibility to have submitted that to check it.