someone help

ok so my brother we have a very weird relationship but long story short im visiting for summer and ever since ive been here he has treated me like shit but i cant do anything about it or he will try to hurt me physically...i dont know what to do anymore hes making me cry like everyday and insulting me 24/7 but none of my other family seems to care that much... and they just leave me being upset and go hang out with him and go out and have fun together. Im only 14 and hes 17 and much stronger so i dont know what to do anymore. (he has previously tried to fist fight me but my mom told him thats ‘to far’)