I feel like a child due to one of my traits I have. Specifically its often more time with my brother than others.

My brother will ask for money and cigs and so on... He's down on his luck now so i'll throw a few bucks to him if I can, or sadly if I can't.
I just don't get me with him. I told him twice I may have trouble with my rent and all, yet he calls 2 more times and texts asking for money... I cave in and give it to him, I don't want him mad at me or if he is in a mood swing get really mad.
We have a troubled past, its hard to for me to explain. I don't want to paint him bad, he's a good guy but has terrible mood swings- bipolar... one time he scared me so bad while in an argumen a few years ago that I peed myself due to he was hitting walls and looking at me intently and yelling at me.... I just stood there waiting to be beaten.

I get told our past is why the way I feel. I guess so but I want help him unless its not for gas and food and so on...
I don't know if I could honestly ever tell him no to his request when he is persistent in the way he gets.

Put my self in a bind just for him to get Detox. What's wrong with me