Monitor him. You're not going to get him to completely drop the habit if he is already at the point of smoking every single day. So maybe try to allow him to smoke but not every single day. Make sure his priorites and responsibilities are still in tact. You can be a responsible person that smokes weed. If school is inportant, then make sure his work gets done and grades stay up. If he works, make sure he goes to work when he has to. If he plays sports, make sure he keeps it up and does not choose weed over being active. So its kind of like making sure the weed habit is in moderation. Smoking everyday is too much, trust me he will get burnt out quickly and its not fun. But smoking weed as a reward or just on the weekends and a couple times durng the week, so long as his priorites are still being conpleted, then it should be fine. Keep in the look out for further drug use though.