While he may not drink as much as someone else, and while he may be functioning well right now, please keep in mind that alcoholism is progressive. It will get worse. It never gets better without help. So, if he is an alcoholic, there will come a day when, yes, he drinks just as much as "they" do and his life will start to unravel, which means yours will too.
I hope you will put any plans to have children with this man on the back burner until this problem is resolved, one way or the other.