"Home"

I am a 16 year old girl that has dealt with both physical and verbal abuse my entire life by my older sister. Ever since the last few years the physical abuse has calmed down a lot because I have learned to just not fight back and to not come out of my room, but I still have to feel threatened and unsafe whenever I am home. I've tried telling both of my parents that I can't be home and be happy and that I feel as though I'm abused but my father disregards it and my mother just says she doesn't know how to handle the situation (therefor she doesn't) my sister will be going off to college soon, but I still have to live with her for summers, holidays and weekends. I am considering moving in with my grandparents but I don't know how much of an adjustment it would be. I'm just looking for any advice, if there even is any on this situation.