Alcoholic Brother… feel like nothing helps.

I've been through the dying process and death of a brother. The part leading up to it can be most painful. I do not doubt that you are having similar feelings.
But what to do about it? There is likely little you can do to change him. So don't worry yourself thinking of how to do that. Your sadness and anger are something that you can control! When those moments of sadness come, thing of the good times that you had together. Smile about the funny things. Remember him with fondness. Change your thoughts to look forward to the times that he does show up in your life! Love him profusely when he appears, and take pictures!
When he does come, and after you have shared fun and joy, ask if there is a way that you can contact him in case of a family emergency. But don't count on his promises because you know he doesn't keep them. But you can keep your promises to him. And you can let him know that you will always be available for him.
You never want him to take advantage of you, but if he does ask for help, be prepared with your answers. Know what you will say in various situations and know in advance where you can go to get assistance that he needs.
You don't have to stop caring about your brother. But find the best attitude that keeps you and your family healthy.

Be there for him and respect his independence. He has a serious illness which you can't do anything about; he can only find help for himself.
You can expect that 9 times out of 10 he will end up getting drunk and be too hung over to meet up with you if you make arrangements. Don't give him money or enable his habit, but be loving and accepting of who he is and don't mention his drinking; it won't help your relationship and he already knows he has a problem. Try to make any time you spend together positive and judgment-free. I hope your brother is okay, having a good time somewhere with people he trusts. Try not to worry or let it upset your life.