Sounds to me you need both carrot and stick. What he needs is a project that his clearly his in the eyes of his peers, has tangible objectives, and a deadline that is tight. The probability of success should be low (The first time around). At that point you should have his attention and it should be fairly obvious to him and the employer where his skills most need improvement and courses should be offered to him to improve those areas.

Upon completion, rinse and repeat as necessary. Any nice guy that isn't motiviated by that cycle of opportunity and challenge, deters from the success of a team, and needs some unemployment therapy in order to get his priorities straight.