Can this heavy drinker aged in his 60s reform?

Case scenario

Bill is aged in his late 60s and has been a heavy drinker for many years. He lives alone and from time to time becomes homeless. Bill had a good spell recently: he attended a rehabilitation centre, stopped drinking for a few months and improved dramatically. However, he relapsed yet again and is now homeless once more.

Bill’s son Peter, a journalist, does not know what to do. He cannot bear to turn his back on his father, but he also thinks that his attempts to help are a waste of time. Peter asks for your advice.

What do you tell Peter?