Okay, I don't even really know where to begin with this... Sorry, it may be long but please read if you have time and can advise me..
I know this might sound like an awful thing to say, but my sister is ruining my family and the situation at home is making me depressed. I now enjoy work more than home because it is always so stressful and my sister argues with everyone, everyday. And I don't mean a small argument, I mean screaming, eastenders-style arguments. She looks down on everyone else and is incredibly self-centered, takes advantage of both my parents and is very disrespectful and nasty to them. This then makes me fight with her often as I can't stand seeing her being so rude to my mum and dad, who do so much for her. What's worse is that whenever anyone tries to confront her about her behaviour, she makes out that my mum (or whoever it is) is being nasty to her or is "bored" of her or something. Whenever anyone picks her up on something bad she has done, she starts WAILING and crying and even literally screaming sometimes.
She clearly has a serious issue but she is so insensitive, manipulative and spiteful that I am finding it incredibley hard to be sympathetic with her as I have put up with this situation for so many years and am tired. She was a bully to me as a child and has been jealous and hateful towards me more and more over the years and it's effecting my life as well as the rest of my family. Even when I was diagnosed with a mental issue of my own (BDD) two years ago, she used it against me, calling me ugly and deliberately bringing it up to make me feel ashamed and I feel like she keeps being forgiven for everything and that it is just getting worse and worse! She is very sharp-tongued and has barely any empathy for others (when my grandad died all she did was make nasty comments about him since she didn't like him.) and yet my parents are allowing it to carry on since they are worried about upsetting her further.
She over-reacts to everything and one time even punched the screen of our famly laptop, breaking the screen which cost £180. She then refused to pay for it meaning my parents had to. We don't have much money but she seems not to care about my parents at all, as long as she can do what she wants.
I personally think she has multiple issues. She is VERY jealous of me (and my brother, but less so) and hates it when I achieve anything, but goes out of her way to talk about her own talents, and is very pretentious and deliberately talks in an elaborate way, and acts like everyone else is stupid. She is attention-seeking, jealous, heart-less and aggressive but at the same time seems to think she is a victim of everybody else (and I can assure you that is not the case.) making it difficult to pull her up on her behaviour.
We are both students so neither of us can move out as we have no money, but I honestly feel like I would rather never be home that put up with it. But it devastates me that all my family have to live in such a miserable and stressful environment (especially my younger brother who is still a child) and it makes me frustrated and angry to the point of tears.
What should I do? Or what do you think my mum should do? I know she should see someone for help but I don't know if she would go, and I don't think my mum is strong enough to make her go or to speak up if they were to go together.
Any advise is welcome and I hope this post hasn't sounded mean but she really is the cause of so many issues in my family and it is ruining our relationships and our time together. Nothing is fun or relaxing at home any more and it is like we are all under her control. I want to move out but even that would not help anything as I know my family would still be stuck in the same situation. I also doubt she will ever leave home as she is so dependant on my parents and is also bad at holding down jobs (too many days off etc) and snobby about taking "ordinary" jobs so I can't see how she will get a job at all, since she won't just walk into an amazing one.
I just want her to grow up and stop having tantrums and being jealous, and I want her to realise all the things my parents do for her rather than just pointing out the "bad" things, which are VERY often extremely exaggerated.
Any advice would be amazing. Or even if someone has a similar problem. Thanks.