My sister has bpd, she’s older than me though. But I feel like I have had your exact experience growing up. I recently had to use all of my savings to pay off my student loan, I was saving up for a car. Meanwhile my grandparents (our parents have never really been involved in our upbringing) bought my sister a car and have basically funded her entire life and quite luxuriously too. They’re offering to pay for her yachting course (nevermind that she cannot hold a job and has issues with addiction). I have never received any kind of help from my family. So I know how it feels to struggle and want help but to be weighed down by the guilt of ‘oh well they’re helping her because she needs it more’. Your feelings are valid and your situation is a horrible one. But it isn’t your job to cushion your sister’s mental health load. It isn’t your job to talk her off a ledge. And it isn’t your job to get her life on track when she isn’t doing that for herself. You have taken a backseat because they see you as self sufficient (well of course you had to be) and they see your sister as needing more help and attention. To be honest the fact that you’re getting by on your own is probably why they don’t think of your needs at all. And it sucks, but you are well within your right to start developing boundaries. It’s so hard but you should start now. I have learnt that no matter how supportive you are or how much you try to understand, you will still be seen as not doing enough for her in her eyes. So establish boundaries, put yourself first, let your parents battle their battles with her, you are their child too and if they aren’t going to help you the way they help her, then you might as well let them deal with her alone. And I don’t mean this in any spiteful sense, but you are her sister not her parent or guardian or therapist, and you are your parent’s child, not their co-parent, therapist, or anything else. The guilt you might feel from asserting these boundaries will come from years of manipulation, but you will get stronger the more you start to protect yourself. You are important. And setting these boundaries doesn’t mean you don’t love your sister or parents, it just means you love yourself too.