Thanks for the feedback - it gave me the answer I knew was the only one. In the end, it's up to my brother and SIL to take action - it's not going to happen without that, alas, as the daugher and boyfriend are just far too comfortable with the status quo to want to shift on their own.

Hey ho - you just can't help other people sometimes....(ie, I can't help my B and SIL more than by telling them what they need to do....but they won't, I know. They hate confrontation so much.)

Thanks all - Julie.