First of all its his decision if he wants to quit or not and you need to respect peoples choices, second i have been going through an extremely tough time with my parents and i am now getting tested weekly. it sucks at first but you learn from your mistakes and now i only smoke on weekends and manage to pass my tests by working out and drinking shitloads of water. It is better to only do it on the weekends for me because i can concentrate on school more, i get more high , and it saves money. hang in there it will all work itself out
peace out