My friend is in smokin habits now and i don't really know what to do.should i tell his parents..??

Don't betray your friendship and tell his parents. Help him realize it just doesn't make him look cool and he stinks in a joking but seriious way =P Tell him that coming from a girl....alot of girls like a guy that doesn't smoke, it'll make his breath smell like **** eventually. Maybe that'll help. Your doing a good thing by realizing yourself it's a bad habit. Good for you!