'this opportunity' = marriage to you??
If he needs a marriage or a good wife to get rid of his stupid and immature habits, then sorry to say, the guy is not a good candidate.
I would want to start off as a partner and friend to my husband and then be more to my husband, as and when time demands. If I were you, I would not take (these types of ) additional responsibilities right in the beginning of the relationship...(such as helping him get rid of his habit) and therefore, tilt the scales.
The situation would be different if he had already given up all three of his habits.
this opportunity to the guy may mean moving to a new phase in his life.
I dont think he is saying that he would need her help in doing so, is he?
giving up social drinking is not a tough thing, its less physical and more of a
giving up social drinking is like giving up eating donuts, at some point you realize it is doing a number on your waist and heart and you just stop doing it.
let us not confuse the terms social drinker with alcoholic, very diff thinsg and very diff inssues in trying to give up.