Always safer for them on a cot in a cage drug free instead of bailed out where more poison to put into their bodies can be obtained.
If your brother really wants to get clean he will and he will find his way down that path. There are social workers and drug programs in jail.
I couldn't agree more with what zozo said. Doing the right thing and playing the role of perceived bad guy keeps you true to yourself and is most loving for him even if it doesn't feel that way or more importantly that he doesn't see it that way. You know the truth and that's all that counts.