A lot of people like this exist though. Toronto has a huge problem where the homeless refuse to go to shelters because they don't want to be told they can't use drugs. So they make the conscious decision to opt out of society and stay on the street.
There is no way to get through to people like this. Even if they had their own place they'd probably OD before the end of the week with all their extra comfort and freedom they have. Some people can't be helped and that needs to be something people are more willing to accept.
As for your friends, popping opioids like candy is a poor decision even if your doctor is prescribing it to you. Intelligent, educated, and capable adults should be held accountable for their own decisions when they turn out to be poor decisions. The opioid crisis is not society's fault.