I can relate to the terror and humiliation. I too have a hard time feeling anger towards people who abused me. I'm a much easier target and, it seems, safer. But you aren't to blame for anything others have done to you. It's taken me a long time even to be able to say that much.
A friend of mine wondered why I felt nothing about being 'pantsed' during P.E. class. I guess I got used to it, just as I'd been used to torture and abuse earlier in life. I also have things I don't seem able to remember. All I can say is, what you experienced was horrible, especially with your brother being involved.