13 year old touching a 6 year old boy

I have a question my nephew is 13  old and my son is 6 years old. I have a 9 year old daughter as well. My children went over to their grandparents one weekend and my nephew was watching a porn site while my son was in the same room. He went and asked my mom what "sex" is. Well later when I came to pick up my son I found this out and was very upset. Later that night when my husband went to have the father/son talk about what he saw on the computer we found out what really happened.
My nephew asked my son to have sex with him. He asked him to go to a hiding spot with him and if he didn't he would not play with him anymore. My son told him no and my nephew told him that they would watch this video to see what they should do it was a porn video. My son saw the video and told him to turn it off because he knew it was wrong. Then my nephew asked if he could kiss him and then he pulled out his penis and showed hisself to him. My nephew is already seeing a pychologist for other stuff so she took him to see the dr because my nephew was denying that all of this happened. Well he admitted that he did all of this and by law the dr had to call CPS. Well CPS dropped the case before even talking to us due to he is under pchyotherapy right now. The dr's and CPS called this normal behavior for him and that children experiment. I totally 100 % disagree. Can you give me your advice please.

[Kevin Kennedy, Ph.D.]

No, it is not at all normal for a thirteen-year-old to expose himself to a young child and request sexual activity. Nor is it normal to expose the younger child to pornographic material. I understand the point about protective services not intervening because your nephew is already in therapy, but they should have spoken with you in the name of a thorough investigation. The only part of the experiences that could be regarded as normal is a thirteen-year-old viewing some inappropriate material. Such things occur, even with teens who are not in therapy. It;s not to be approved (i.e., by parents), but in and of itself it is not alarming. Given that this boy has problems already, though, viewing pornographic material is not going to help and parents should be pretty vigilant about it.