Could you get him to do some volunteer work to try & nudge him gently into the big wide world? Or could you find some odd jobs around the house - like clean the guttering, etc... that he can do to 1) get him out your hair a bit & 2) to try teach him the workings of maintaining a home??

Is there anything he's particularly interested in that he could study? Like maybe welding, woodworking, etc...?