How would a doctor treat an 80-year-old drug addict?

Hmmmmmm: Drug addicts tend to have shorter, unstable and unhealthy lives. 80 years old and drug addict don't tend to go hand-in-hand. If we are talking about someone who is using opioid pain medicines for pain and is physically dependent there's probably not an issue here. In that scenario the 80-year-old is using the medications to treat a medical issue. I need more information to give you a better answ.