About two months ago, my 13 year old brother was caught touching and rubbing his 6 year old sister's private parts. My dad talked to him about it, decided it was just curiosity, and choose not to do anything about it, besides scolding him and punishing him for lying. At the time, every instinct told me that this wasn't normal, and that we should seek outside help, but my dad firmly disagreed with me. Now, I found out that, not only did he do it again, he's done it at least one other time. He never came forward and admitted it; both times he was caught in the act and only admitted it after extensive questioning. When he was asked why he did it, he said because he thought he wouldn't get caught. He seems to show very little remorse about it, even though he says that he knew it was wrong and that he felt guilty. My dad finally agreed that this is a problem that needs to be addressed, but he doesnt want to call child protective services. I feel like it's my fault that it happened again, because I didn't report it the first time, and I'm terrified that my brother will do it again, not just with his sister, but possibly with one of his younger brothers ( one is 11 and the other 8, but the 8 year old has some developmental problems). I know I need to report this to child protective services (and I hate myself for not doing it the first time), and I'm going to, but my dad wants me to let him handle it; he says that their his children, not mine, and I don't have the right. How can I convince him that reporting the abuse to the authorities is the right thing to do?