15yr old pregnant with a 20yr old wtf!?

So my boyfriend's aunt in law has a niece that just recently had a baby. She is 15 and the dad is 20!!!!!!!!!!!!!!!! To make matters worse he is living with her and her parents. What kind of loser does this? I feel like her parents need to be reported and sterilized. Some people say well it was her choice um not really she's 15 she can easily be coerced by the sick f*** of a dad he's 20! He's an adult she is still a baby. He clearly needs to be reported but someone needs to do it and they aren't, the parents should be. It just makes me sick! I know there is nothing I can do about it and I should just let it go and understand it happens everywhere but it just frustrates the hell out of me. What can I do? I guess I don't have much say seeing as I'm not even a real relative just a girlfriend (of 5yrs) but I just don't think this kind of thing should be happening.