I'm going to update my post, but just going to post this quick bit.
Bi polar imo should be ruled out as it is drug induced. I highly suspect codependency issues causing thoughts of anxiety, abandonment trauma causing feelings of depression, and an inability to express and deal with the emotions involved due to not understanding how to process or even comprehend these emotions...
I say this from my own experience understanding my issues of low
Emotional quotient. Helping this person to understand that will be the most theraputic thing for them. They need to understand the root of why they are relying on not just the drugs, but all these dealers and friends vs. their own strength.
The overuse of mdma, possibly other dopamine acting amphetamines, and who knows what else is definitely doing long term damage. I can't recommend any advice as honestly you probably have better resources to deal with it without or without rehab. Just remember nothing will work if this person is not ready for it to work. Sometimes all you can do is let them hit rock bottom and the only thing you can do is offer to support their recovery.
Whoever says the OP is wasting time is wasting their own. When people are given up on it affects their ability to trust themselves as well as anyone else.
Edit: I realize I'm posting super late and wish the best for the op friends. I understand wanting a confession of addiction although that should be for himself only and not for the comfort of those around him. I was told mdma does have irreversable binding action in serratonin leading to the physical symptoms bring fatigue and twitching mainly.... I've found no documentation to back this up. If any mental health medication is needed it is only to manage the damage and stress from the overuse of pills. Really though a active and healthy lifestyle along with a friend who will be there for them always or a therapist to understand and manage the emotions that come with the responsibilities of age. Anyways I send my best wish of recovery to your friend and their situation.