He is definitely a survivor, as you say, and yet the kind or amount of help he was offered or received or accepted or whatever those many years ago was insufficient for the long haul. Being sober proves abstinence, but being sober does not treat the underlying causes of one's being irritable, restless, discontent and so on. As others have said, there is really nothing you can do at the moment other than to continue caring about and for him as best you can...and then hopefully a day might yet come when he will want to talk with someone such as myself who has been there and has been shown more solution.