I've been wondering about this too... exactly how do we know they aren't in current danger with the in-laws??
Some may say that it would be preposterous to think so... as the in-laws haven't been charged with a crime, nor have they been named persons-of-interest, nor has anyone testified that they have observed them be unfit guardians..., or acted violently towards the girls, and they obviously love them and would keep their best interests at heart... so surely, the girls are safe with the in-laws, right?
But wait... hmmm... come to think about it, all of the above statements can be made about BC as well! Wow!
Why not err on the side of caution, and give the girls back to their biological father until this mess is sorted out?