family abuse is treated differently

Does anyone else feel that abuse within a family is treated differently than abuse between strangers/partners/friends? Whether it be physical, sexual, verbal. I have an abusive brother and I am always told to forgive him, forget it, he's your brother etc. however if this was a boyfriend or a friend or even a stranger that was treating me like this I'd be encouraged to call the police and cease contact with the abuser. Does this happen to anyone else and how do you escape it?