My  brother  I knew had been smoking weed and he was caught at home trying acid. But tonight he was telling me about all the different things he’s tried the main one being dxm or dextromethorphan. He told me he could tell he was beginning to crave it and so stopped using it, but plans on doing it again after about 2 months so that he can tell he’s in control. He’s researched most drugs and has a fascination with them so when I try to be logical with him about the negative effects he counters with the knowledge of how to “be safe” while abusing dxm. I’m worried this is turning into a bigger problem than he realized and would appreciate any advice on how to approach this without him loosing my trust.