If he does it enough, you won't have to worry about what to say, unfortunately, because he won't be there anymore. I don't know an answer. He has to find it within himself to be responsible about college. His bipolar just complicates the situation. In my experience, it's not uncommon for someone with bipolar or another condition to really struggle in taking responsibility about their education. Some people have a change of heart when they come close to being kicked out, and other's don't. I really wish you the best. Life is not a game, yet it is competitive. You can help him recognize that by confronting him forcefully about screwing up. It could cause a blowup. He probably won't like you for doing it.

Hey, my boyfriend is actually on the brink of being kicked out of college at the moment, so when i go around to his house tonight I'm going to sit down and do the unfinished coursework with him. I've got to be firm yet try to understand what he's going through. Thanks for the reply!