Your son has ADHD
and all people with ADHD are prone to get used to substances. As far as drinking is concerned, its OK as far as it is social and with in limits. If you say no to everything, the child may resent and not listen to you at all. may be you can focus your efforts towards marijuana which is not good and he should stop it immediately. May be you can have a discussion on the problems with marijuana use in the family and instead of forcing him, let it be a combined decision to stop marijuana and continue with only occasional alcohol. leaving marijuana all of a sudden will not cause any problem and he should leave it. If he is not cooperating, then may be you can get help from the school counselor who will be more than happy to help him.
As far as interaction of Vyanase with this cehmicals, there is no major interaction but then all drugs are bad.
Hope i am able to solve your concerns.
thanks. have a nice day.