Sounds like you don’t like her family, probably for good reason, and you resent the money you paid to help her out when they first started dating, and for the wedding, when they’ve contributed nothing. And fair enough, I suppose. I know I’d resent paying $100 pp for people I don’t like and don’t respect. It also sounds like you perhaps resent her a little for being a drain on your son’s life while she was going through a medical crisis and she’s not the woman you would’ve chosen for him. Also, fair enough, you’re a mom, entitled to her feelings. And perhaps you feel like you should be held in higher regards for helping her out (this is a bit petty, though).

In any case, the issue now, is where you want to go from here.