Oh, honey, I'm so sorry you have to go through this. I agree with January - he may be frightened of what he doesn't understand.
I don't know exactly what it was with my youngest brother (we were really close) until I started telling him about the abuse and my "other selves". He used to come up with all kinds of theories, as to what was really wrong with me. We lived in New Orleans and the rest of the family where in Michigan, where we were raised. One of my sisters talked with him a lot about me, never asking me. Anyway she wrote me a letter saying I no longer belonged in the family. I lost my brother in 1995 from aids and he went, still obsessed with trying to fix me.