I don't want to de-rail an already sad thread...Tom was a pro, obviously loved what he was doing and gave it his best to the end.
However, as was said, those drugs *do* have their place, but with prior addictions etc they ought to have been given with the very very very very very very most extreme caution and monitored stringently - and it appears (as is all to often in the entertainment biz) they always find a doc willing to look the other way and get the scripts refilled at will.
So sad - he ought to have took some time off, got his pains dealt with.