My daughter is 12 and my nephew is 17. She said he showed her his penis and asked her to touch it when she was about 9. She said she did touch it, but did not remember what else happened. Since this happened, he has been going into her bedroom while she sleeps, but only remembers him touching her back a few times.
I just found all this out 2 days ago. I reported this to CPS. They came out to talk to me and briefly with my daughter. She is supposed to go tomorrow and talk to a professional as a representative from CPS, Law Enforcement and the prosecuter's office watch from another room.
My ex husband is not wanting her to go to this interview. He said, "she told me she was fine, and I believe her". He is adament about not making her go. He said it should be her decision. I don't want her to have to go either, but I know it needs to be done. He doesn't think she should have to go to a counselor if she doesn't want to. It is difficult to get through to him how important this is and she is not mature enough to make these decisions.
Any advice would be welcomed.

Have her go and even get professional counseling to be sure. She may have told your ex that because he was a man and did not want to talk about it to him.

Next your ex is a lousy father for not wanting her to go ahead with his.

Is this a nephew on HIS side of the family, a brother's or sister's son?

I should have stated that my nephew is my brother's son.

Is this a nephew on HIS side of the family, a brother's or sister's son?
He is my brother's son.

If the nephew is doing/has done this not only to your daughter but also to other little girls (and boys?), he needs to be stopped.