In chapter 12 of Lord of the Flies, what does Ralph realize about Bill (specifically) and about the others?

Who is Bill?

I have no idea. I haven't read the chapter fully. o___O

Oh, I remember now. Bill has fallen under Jack's spell. He has "drank the Kool-aid" so to speak. Bill and the others have ceased to think and are merely dictated by Jack and their primal urges.

Could you use this in more simpler words that are easier to understand?

Bill blindly follows Jack; he, like most other boys, do what Jack tells them to do. They really believe that Jack is powerful and that he offers them protection. Jack offers them their simple wants (hunting, killing, no responsibilities...).