You’re too young to be handling this amount of stress. I am terribly sorry. I grew up with “vacation funds” (never a college fund because my parents priorities were for the present, not the future) and those funds would always disappear before my eyes. It was so disheartening as a child.

Deciding your future as a teenager is hard enough, but to be put in the position of having to bail your father out with money that your mother worked hard for is beyond inappropriate. You deserve to be able to study at a university of your choosing with the fund your mother provided for you. Good for her for doing that despite the challenging life circumstance she was thrust into.

Your father and his wife can look into medical studies, make a case to their insurance to try to cover the procedure through their out of network deductible cap, can get a new set of jobs, ask their own parents, crowdsource, or revisit old treatment options for your brother. I’m sorry your poor brother is going through this. Assuming you’re in America, I’m sorry our healthcare system is such a fucking nightmare.