I guess I'm questioning the same thing? Isn't BIL paying for the trip? I guess your W will want/need spending money of her own even if he is paying. I don't know if it's fair.. I mean if it's just a tit for tat type of thing...I understand the thinking behind that you should be able to spend as well. If W is going to go out of budget or dip into savings to do something then you should to? Is that it? Or do you just mean you need extra sessions to deal with W going somewhere with her brother?