Anonymous wrote:OP here. I am more and more inclined to decline (pun?), but strangely bro is pretty set on us coming.
Yes his work is paying his expenses. He casually mentioned it felt weird to go to a free event if he ended up paying for airfare for someone to watch the kids.
Right now it's getting even weirder- they don't know if they'll have a nanny lined up by then (since the current one is leaving them), so he may end up staying despite me coming (as I think he realizes it's too much to ask of me to drag two kids along to activities of the third). Which would put me in a weird position, do I reimburse him the airfare? But I can't really afford it, nor would I really want to, as the timing is not great.
Yeah, I think I will need to decline politely altogether.
Could it be that your brother is having marriage problems and needs your support somehow? Geez, it sounds like your SIL has the upper hand in their relationship. He seems to be stuck. He needs to tell your SIL that she can not go on her trip that week. Maybe he suspects she is cheating on him and he needs you to come over so he can spy on her

Something is not right there, and he seems to need you. Perhaps take a pass on this one and see what happens?