Not sure if this is an "etiquette" question so please feel free to move this if appropriate!
My folks originally offered to kick in a certain amount of money for my wedding -- bonds that they have always held for me that they say are my money. When it came time to guest list, because of large families there were some people, mostly my non-mutual friends, that we felt we couldn't afford to add. My parents were bothered by this and after pressing me for months and me saying it just wouldn't be responsible (they wanted us to count on non-attendance which I know is a no-no!) they sent the promised check but with an extra $1K to cover those extra friends. They would not take it back. This was obviously VERY generous of them (despite other parent issues I've had).
Well fast forward to today, we had over 30 declines, mostly my family. We got our final bill and it is still a little over $2K under what we'd estimated even before those other friends were added. His father also stepped in last-minute to cover our bar, which will shrink the total cost further. So now I'm conflicted: am I obligated to give that $1000 back to my parents? Should I ask? I have a feeling my FI would say no but I want to do what is right. We definitely have tons of other expenses that that would help with, but I don't know what to do.