My son has a friend named Abigail and my son and Abigail are very good friends. I would have never suspected this at such a young age...

I work late, and my son always brings Abigail home as well. They walk to my house and stay for an hour until Abigail's mother can pick her up.

Anyways, I got home a little bit early today, and I heard noises coming from my sons room. The door was open a crack so I peeked in wondering what that noise was.  My brother was sitting down on his bed naked and Abigail, who just turned 10, is kneeling on the carpet sucking his ****.  I saw him say "stop" and she backed off for a minute. Then he shot loads at her and her face was covered in it and she was smiling.... Then he got on top of her and did it doggy style.  When she left I confronted them and told her parents. They are concerned as well, but what I am really asking is what I should do. There was a homemade porn playing on my sons iPod while they were doing it and I didn't know why to do, he was humping her and all that.... I don't know. I'm wondering what to do.... My son said they had done this before and that he has shot loads into her before and her mother says she's been vomiting and I don't know what to do. I feel so bad, I don't know if she's pregnant.... Help!