I'm always kind of irritated when these all-forgiving heroines just ignore the suffering they've been through. Your sister has been repeatedly stealing all the income you're earning to take care of her while contributing nothing to the house, and she's been doing it to try to pay her way into being a good person. Yes, she missed your parents, but how much can she make others suffer for that? If this situation were happening to someone else we wouldn't be expected to just be okay with it.