What would you say to this person to try to convince them to quit using drugs and get the help they need?

Pretend a friend or family member has started to abuse prescription or illegal drugs. You have noticed a change in their behavior and are deeply concerned for their well-being. What would you say to this person to try to convince them to quit using drugs and get the help they need? How would you convey this message to them (in person, via e-mail, phone call, text)?