I would agree that his time of play should be limited, but we know we all had to start somewhere.
Recently my brother picked up the game and we set double par as his limit. We had to tell him that good shots on the range would transfer into lower scores on the course. After enough practice he was able to post decent scores, with a dead on 100 this past weekend. If he never took any time on the range he never would've gotten there.His feelings weren't hurt, but more happy that we wanted to help him. Just encourage him and he will realize that your giving helpful advice, not criticism.