Simon,
I've been in a somewhat similar situation recently. Rather than go into a long story, I'll just say that you are correct in thinking that your brother may be interested in that job in order to harm another child. I talked with my therapist about this a lot. I ended up choosing to confront my father and it has been very difficult since then. But, he won't have a chance to harm anyone else now (most important to me is my daughter). I would never advise that you confront your brother or your dad until you discuss this with a therapist. At the very least you should work out a plan like is discussed in the book Courage to Heal and the Courage to Heal workbook. (These books can be found on Amazon.) What a tough situation for you to be in. (((((((((((((Simon))))))))))))))))
Elizabeth