I spent a lot of time re-writing this to be as respectful as possible to all the parties here, most of whom I know very well.
The biggest issue that AD had was that he was allowed to use, both recreational and prescription for years unchecked.
I love his parents, they are both amazing people, but they refused to believe he was using in high school, even when those that personally witnessed his use expressed concerns to them.
The first time they recognized that he was using was when he failed tests for recreational drugs at UT during his freshman year while he was redshirting and rehabbing from his shoulder operations. They wouldn't have been notified abut it, per UT's policy, but members of the coaching staff they were close with made them aware. This is where their belief that he did not start using until college came from.
He attended counseling, per UT's policy, and somehow did not fail a test under Kiffin. He never tested positive for painkillers for the same reason Ainge never did, he had a prescription for them and the standard tests are only done for presence, not amount. His use escalated during the fall of 2009 to the point he started losing weight during the late part of the season. A member of Kiffin's staff told me later that he estimated AD was around 200 for the Chick-fi-la Bowl.
I do and always will have a great deal of respect for the way Dooley handled the situation. He saw some of the problems and wanted to help. Instead, it became an ugly public spectacle. Dooley hoped that by sending him far from his comfort zone, he would have a better chance of kicking his addiction. From all reports, he was clean in Arizona. Alabama vetted him HEAVILY before offering him. Saban spoke to several people from UT that had been involved in his coaching before taking him.
Ultimately, the draw of addiction haunted him until the day he died. I don't know if he used once he got to Alabama, but find it hard to believe he suddenly relapsed on vacation and ended up dead.
People look for someone to blame, but I don't think there is blame to be had in this case. A lot of people tried to help him, a lot of people failed. Might have helped if the issues were addressed earlier in his life, maybe not. No one will ever know, but it's senseless to try and assign blame to anyone.
May he rest in peace and both teams play in his honor Saturday.