<human>: Provide a brief overview of the text.

About a month ago, my friend got his first girlfriend. I was excited for him, he has quite severe Asperger's syndrome and so he has had difficulty finding a relationship. 

But he went on to tell me, that this girl is 14 years old. I've tried explaining that it's illegal, it's morally wrong, it's socially unacceptable, but he doesn't care because they're "not doing anything sexually". 

He also feels he can talk to me about it whenever he wants, which I don't like, because quite frankly I find it disgusting. 

I feel like we can't even be friends any more because it has gotten so bad, but it's like he's a little brother to me (despite the fact that he's older). That's okay with me though, but I still feel that he's (unintentionally) taking advantage of this silly little teenage girl. 

Any suggestions?
<bot>: Asperger's friend is dating 14 year old and I don't know how to make him realise that it's disgusting.