I agree with the other posters who suggest that you lay it on the line with him -- be specific and upfront.

I would also caution that lots of people don't want to commit, depressed or not. I would not get reinvolved in a relationship with him if I wasn't willing to accept the unclear path he was willing to commit to in the spring. Therapy may not make him like the beach or more willing to move his heavy bookshelves.