First one: I would confirm my suspicions first and then jump into action, exposing the group. They would stop using drugs.
Second one: I would snatch his cigarette. I would talk to him about how much just 1 cigarette can damage his lungs.
Third one:
I would tell her about how drugs, tobacco, alcohol can effect the baby. {{{do not write this the same way i wrote this, and u would have good answers}}}}