I hope that once the money runs low, none of them - including your mother - come to you, but they probably will.

Stay as far from this mess as you can, and stop talking about it with any of them. In fact - I hope you're not even seeing them more than once or twice a year, if that.
Your mother is putting herself directly into the mess - starting a business with your aunt, and letting her move in. You don't need to do the same. Learn from their mistakes, and keep your distance. You owe them nothing.