He started using those drugs to help deal with the stress and anxiety of his wife's cancer diagnosis, and ended up hooked. If you decide not to believe that, cool bro.

It's a perfectly valid point that he was giving out advice and helping people with their own crumbling existences, whilst his own world was falling down around him. That's quite a common occurrence; people being able to help other fuckers sort their lives out whilst at the same time can't do it for themselves.

At this point I'm actually going to be very surprised if he doesn't address it properly in the foreword or introduction to the upcoming book. I think there would be no better way he could possibly do so.