Replying to Drugs

My bro fairly recently turned 16, he started smoking weed about a year ago now (not legal in NZ yet) which was fine, but more recently its been nearly a daily basis, he yarns on all the time about his mates doing MDMA at parties, pretty sure he's into the same stuff and the other night found codeine in his room he's "using to help sleep" - should I beat the shit out of him? on a more serious note - should I genuinely be concerned? I never really went through the same shit