What is a good word?
After an incident with some boys teasing the girls, a sweet lady told her son to be a "big brother" to me and take on anyone who tried to tease me or mess wih me, because he did that for his sister. I want to find a word that kind of describes the position he in. Like "he's like a brother to me, but he's not actually my brother", kind of thing. I thought about surrogate, but that means substitute and he's not a substitute, more of a... I don't know how to say it.