u/Keigoshoe

I posted this earlier but it got deleted so here it goes again. My brother, who is over 18, was an addict when he was younger. He went through some shit and got sober; then he just recently, within the last few months, got back on substances. My mom speculates but is very sure he is. I, however, know for a fact he is. I don't want to tell my mom, as she is already beside herself and she doesn't even know for sure yet. My other siblings and I all know he is using again and don't know if we should tell our mom yet. Our dad is useless and is to blame for how he got this way. I'm so lost on how to help him. I know I can't really do anything, as he is over 18. But how should i be around him? Should it be more tough love or kindness? I've tried being kind and not trying to push him but it's not working. I'm very confused and would appreciate any advice from experience you guys have. Thank you.