It also sounds like this family didn't have a lot of money to throw around feeding unexpected guests. Yeah, sure, a plate of food would totally ruin them....
I don't believe its our place to judge how much money one has or doesn't have. Feeding her once would set a precedent that may mean feeding her three nights a week and that really adds up. I know I can't afford to feed an extra person.
Yebbut - Dan ate at her
house at least once a week, right? So, it's OK for him
to eat at her
house, and not reciprocate? Not in my book! When our kids were little, we made sure that a) they came home at the other family's dinner time (repeated reminder to the children/teens, and lectures when they failed) and b) when the dinner was a prearranged thing, we made sure we did reciprocate and fed that child/teen. Dan and his lovely family sound like pigs to me.... But any relationship
that ends up that off balance breeds resentment sooner or later.