So my sister ( the one I thought was self-righteous and arrogant ) and said she hates Dad as much as I do, and that she hates it here. She asked me if I could keep a secret, and that secret was that she was moving into Charelle's (the sister my Mum outed to my Dad) house until she could get back on her feet. She said she feels sorry that I have to stay in this "hell" for another 3 years. I said yes. I've been waiting for her to crack (that sounds bad, but I knew exactly what she was doing, and I can't say I blame her.) Since August. But I digress. I just wanted to know if I'd done the right thing by keeping this secret?
Keep in mind that this sister is 19, so the only problem is Mum and Dad eventually finding out where she is, and them finding out that I know.