Hi, and welcome to SR...I'm so sorry you're going through this. The harsh truth is that he is taking advantage of you because of his addiction--alcoholics will use manipulation and lies to get everyone and anyone to support their lifestyle; they will use guilt trips, try to get you to pity them and feel sorry for them, and basically allow you to take care of all their responsibilities and make you out to be the "bad guy" whenever you attempt to set any boundaries.
It may sound harsh, but you are not helping your brother by allowing him to continue to avoid the reality of his situation and his alcoholism--you are hurting him. The only thing that might help (and I say might) is to allow him to experience the consequences of his actions. That is when he will change, if he decides to change at all.
I hope this does not sound harsh...I am just writing from the experience of dealing with my sister's alcoholism. She is 40 and has been an addict for nearly 15 years. She's been in and out of treatment and has never quite taken responsibility for her issues until recently. The reason? She didn't have to take responsibility because everyone in our family was doing it for her. By "helping" her we were allowing her to continue her behavior. I thought for the longest time that I was "helping her" by giving her $, making excuses for her, pitying her, etc. etc. I finally realized that, yes, she is an addict, but she is also an adult, and she should be responsible for her behavior and her addiction. I stopped enabling her and she moved in with my parents--just for a "month to get back on her feet"--that month turned in to 1.5 years because my parents would not stop enabling her. She didn't have to pay rent, pay for food, etc., and they drove her everywhere, took care of everything, etc. So she continued to drink, lost jobs, and drank...and drank. Never went to treatment for that entire time and then decided to move back to the state I live in (my parents live out of state); she was here for five weeks and then got evicted for problems related to her drinking; she wanted to move in with me and I refused. She is now living in a hostel and going to treatment every day. She is mad at me for it, but I believe that if I had interfered again, she would not be in treatment now....honestly I don't know what will become of this latest attempt at getting sober; but I DO know that I am allowing her to be responsible for her actions, and only that will save her in the end.
So...I'm writing all this to let you know what my situation has been and to tell you that I can relate to your feelings completely...it is so hard to imagine someone that we love living on the streets...but I can tell you that nothing good has ever come out of me "helping" my sister--the $ I "lent" her just went to her vodka supply; the times I called her work for her or drove her to the hospital or told her it was okay if she needed a few days off to rest turned into more reasons for her to continue along her destructive path.
I, too, have read Addict in the Family by Beverly Conyers, which is an excellent book...it really puts things in perspective.
Keep posting and begin setting boundaries...when it comes down to it, he is an adult. If he weren't your brother, how would you feel?
Hugs