[shred]

Sorry about the situation, it sounds like a mess.

But, one thing no one seems to have picked up on: if your niece is 18 and the boyfriend is only 17, don't the boyfriends parent's hold the ultimate weapon over your niece's head:

They could have her arrested for child abuse/statutory rape, if they wanted to, I believe. What is the age of consent in the state where they live?