Did I say you should leave him?
You asked whether what you were proposing sounded crazy (telling him to drink at home to save money so you can split the rent). I'm not quite sure why you asked if you weren't interested in the answer.
Where is he getting the money to drink at the bar?
He's told you he isn't even sure he wants to be with you, but he "needs" you because you are giving him a place to live. He is all but spelling it out: "I would like to continue to USE you, as long as you don't make it too uncomfortable for me."
We ALL understand, believe me. We have all done the same kinds of things trying to "save" someone who has no interest in being "saved." And, in the process, we lost a whole lot of ourselves.
You don't have to leave him. But you don't have to take him in to live with you, either.
Being on the street MIGHT help him.