It is an old cliche, but only he can decide if he really wants to stop drinking. And it is worth remembering that many alcoholics literally have no control over their drinking. AA certainly promotes that idea, though some people take the view that a strong commitment to quit is what really counts.
You can do something for yourself though. Al Anon is an organisation for those who are close to people with a serious drink problem. There may well be a branch near you. Here's a link to a 'resource' that might be helpful.
Online Al-Anon Outreach