I have zero experience with-dealing with-drugs so no help there. Sorry.
Your son is putting your family at risk in more ways than one. If CPS were to learn of difficult child's behavior (allowing/encouraging 12 yr old to drink and drug), not to further alarm/complicate things for you, but you run the risk CPS pulling all your kids from the home.
Just something else you may want to factor in to your planning/intervention.
It shouldn't be so hard to parent our kids. Hugs
