Could it be that you think you can "help" him, "fix" him, "stop" him from drinking, have him use you as a "control", keep him in "line", when he falls, pick him up and "dust him off"?
If so, it's an old, old story and leads only to what you describe going on right now. Only he can get sober and if he won't start doing it for himself then he's just going to get sicker as time goes on. This guy can't be the only game in town. Why not do yourself (and him) a favor and get off the bus?
W.