I'm having trouble figuring out what is meant by this:
'Everyone in your family needs to bring enough food for 20-25 people.
So, if there are four people in your family, you are supposed to bring enough food for 80-100 people?
Doesn't make sense at all.
Is it a potluck? That's not how they work. Everyone brings one normal recipe size dish and shares and there is plenty of everything to go around because people only eat a small amount of each thing.
Or is it a BYOFood thing? In which case, you only need to bring enough to feed yourself, so what's with the "food for 20-25 people"?
All that is just my own curiosity but in any case
I'd be rescinding my acceptance and just say, "We won't be able to meet those requirements so we'll have to decline. Be sure to pass our Best Wishes on to Uncle."