Well, if he keeps taking so many drugs then it seems likely by the time Fragony will be old that dude will be long dead.

There is the option of going to him and telling him the truth, you can tell it in a manner that will not outright insult him, tell him you still like him but you think what he is doing with his life is just wrong and that you do not wish to support his lifestyle for long, that you will give him shelter for some time but he should try to sort out his life and find his own place to live.

That way you don't throw him out, you don't insult him, you just tell him the truth, if he does not understand or gets enraged, well, then maybe throw him out after telling him that he is the one living on your boat.