You could say something along the lines of:
"Hey, Friend, what's so good about weed? Why are you always smoking it?"
If he's smoking it for medical purposes, then just drop it, but if it's illegal and he's doing it to "look cool", then I would further ask questions about it.
Having friendship makes you feel not alone and it makes you happy to be with people who like who you are.
Club Drugs (LSD) (Ecstasy)
Cause Rapid Heartbeat which can lead to death and are often used in crowded hot places causing rapid dehydration which can also lead to death
Bath Salts is a Hallucinogen
this causes the user to "see" things that aren't there and is extreme casess they will mutilate their own bodies to get rid of these "things" it also cause rapid heart beat leading to major heart problems<span />
