Get him a 12 step book? Be there for him. He can't and won't quit until he wants to. He must make the decision. Aside from throwing him in rehab (like some do here in the US) there isn't much you can do. All you can do is let him know that you love and support him and want him to get better.

Therapy might help him work out his other personal issues which in turn might help curb the binges.