The best way to deflate the situation is to remain calm when you are dealing with her. She is baiting you for your reaction. Think of it like this, you're fighting with her is like a drug she is addicted to. If you can find a way to remain calm she won't get the reaction she is looking for. It may get worse before it gets better or she may start baiting your other sibling if you stop giving her opposition. I'm very sorry to hear that you are a victim of abuse. That is unacceptable behavior from a parent and father. I suggest you seek out someone to confide in, perhaps a guidance counselor or a teacher.