I hate being ignored. When I ask someone to do something, I expect them to do it, or stop doing it, whatever it is I'm asking of them. That's the mature thing to do, and it's time your son recognized the fact.
Tell him, if you can't be honest and respect my wishes and the rules of this home, then kindly get a place of your own. You can also treat him like a child and tell him, if I pick-up on so much as another whiff of that stuff in the home, we'll be removing your bedroom door from it's hinges.
