@MoralDelemma Your taxes didn’t give your niece free college. First, she would have had to work hard in school in order to be accepted into a college that would give her great aid and that is not easy to do. Second, because of the profile that private colleges ask for, the college would understand in great detail the financial situation of both parents. It doesn’t matter where your niece lives. Mom doesn’t earn anything and dad earns something. Based on that the private school gave your niece a financial package with money not from YOU a taxpayer but from it’s own funds. They get their own funds from donations from alumni etc… Now you could be mad at your family for other reasons but they did not cheat the system on this issue even if they think they did. And like I said, they could get in trouble for screwing with residency for no reason.
So to recap, your niece worked hard in school and is having her education paid for by the alumni of the school based on her need which is determined by the income and assets of both parents.