You didn't Cause it, can't Cure it, and can't Control it. Your brother's chaos and bad decisions are his. Your primary responsibility is your own family, set boundaries that protect them. Yes, we should be there to help family. But if doing so puts your own primary family at risk, think hard about that. He doesn't sound like he's found real recovery. He did 30 days because he kind of had to, is he in a post rehab program? Going to AA, has a Sponsor, etc? Based on your post I'm guessing no.
You don't trust him. Trust your instincts. Trust your instincts.