I know in missouri the parents of the younger person can press charges. My boyfriend is five years older than me, and when we started dating I was thirteen. My mom found out and threatened to have him arrested, so we broke up until I was 18.
I'm thinking that the fact that her mother lets him live with them and is totally fine with it might make some difference. And if it comes down to it, and the state does decide to press charges, maybe they could elope?? Then it would be legal...Not that I think that's a very good idea, but if it's the only choice...
I hope everything works out with them.
Daile