I have a family member that doesn't want to go to parties, but wants their spouse to bring them a plate of food. Isn't this rude? To me, if you want to go, you don't get a take out order! I can't imagine telling hosts 'oh my spouse didn't want to come, but can I take a plate of food home for them'. One party in particular the family member tagged along with us (we asked the hosts if it was OK to bring him) then his wife tells him to bring home a plate of food for her. 

So my mom said to pay for extra and she would kick in half.
Obviously I put more on the plate of the bigger families then a family of 1 or 2 and the ones that had less thought they were getting ripped off. I had to explain that the bigger families got more because there were more people but everyone had the same amount per person