heres what you should do. tell him that alchoal can kill him because he's too young to handle it, so whever he has alchoal, he should give it to you.(that takes care of the alchoal problem) and tell him that weed can be laced with deadly shit, so he shold NEVER try to get weed from anybody except for you(that takes care of the weed problem) now its up to you if you want to give him weed or keep him from it.