How you deal with your brother (guilt, love, man-up, save-face) is a personal issue and probably too emotional to benefit from objective advice.
From personal experience there is a fine line between enabling (a habit) and helping someone needing support get the necessities of life. In my many experiences first-hand and otherwise, it almost never works... eventually the user has to hit bottom, fully admit and embrace the problem, want and seek help, and stick with one or more programs. Too often, (due to lousy (and corrupt) or worthless profit-factory rehab treatment systems) this fails even when and if the user reaches such a point (or is convinced to do it via intervention or loved ones.) And most "users" tend to continue to "want to get high" despite the many negatives. So the negative of you coming down on him might not even gain anything; and some users do sadly destroy themselves (as well as others) while we are waiting for their get-woke moment.
I can offer no great hope, but took the time to write this because you might save yourself an awful lot of heartache and distress by realizing all of the above sooner rather than later. Good Luck.
