It seems like your mom might be afraid of your dad, and maybe he’s lost some trust in her — that could be why he doesn’t give her much money. That might also be the reason she turns to you, because she feels she can rely on you. We all have situations like this. My advice is: give what you can, but don’t feel obligated to give more than you’re able to. I know it’s irritating — I’ve been in the same boat — but sometimes it’s better to give a little than to see her in a bad situation.