In reply to Annoying Twit:
get him some coaching sessions, its the best way to go, they can weed out bad habits and introduce him to good climbing practice which is difficult to pick up on your own.
Any coach worth his salt will be able to do this in a fun way so it wont be to formal but it will have a great effect on his climbing ability.
i would recomend getting hold of Tom Randall, i found him to be very good and a nice fella, he is an excellent coach and has experience coaching youths.