That depends on the ages of both parties, and the specific people involved. Family relationships are not always the ideal. With my younger brother, while I tried to look out for him as a young kid, once he got a little older it became clear that having any form of relationship with him was not healthy for me. He is extremely narcissistic, a sociopath, bipolar, an accomplished liar, and becomes violent when he doesn't get his way. Since my parents were fans of physical punishment, I was beaten on multiple occasions for things he had done and lied about. He was always believed over me, until I moved out at 17 and the things he'd lied about for years continued to happen. So, for the majority of my adolescence and my adult life, I simply have avoided him as much as possible. My mother intermittently tries to convince me he has changed and to give him another chance. He has not.