My wife (38f) and I (43m) are hosting Christmas for the first time in our new home. Ever since I met my wife, we have always done Christmas at her mom’s house. My wife’s brother (33m) has a psychiatric disability (had to google the proper term so I don’t get downvoted to hell) and has 24/7 care takers. He’s been hit and miss for Christmas and we don’t know if he’s coming til the morning of.

Every year it’s tradition to have a prime rib dinner with the family, and my MIL always buys a 6-7lb prime rib which gets devoured, so my wife and I never get to take any leftovers home.

This year, since my wife and I are hosting, we decided to buy an 8lb prime rib so that we had enough to feed 5 people (my wife and I, MIL and her husband, and BIL), along with having enough for leftovers. We made the usual side dishes and made just enough for everyone, but made extra mashed potatoes because I got a new ricer for Christmas that I was way too excited to use (this info is irrelevant, just wanted to brag about my awesome ricer).

After dinner, my BIL breaks out 2 dinner plates from his backpack and starts dishing up the rest of the leftovers. Stunned I asked him, “what cha doin bud?” To which he replies “packing up leftovers for ___ and ___” (his caretakers). I look at my wife, she looked dumbfounded. I look at my MIL and she quickly responds with, “don’t worry, he does this every year”. My wife and I had no idea this was a normal arrangement, or were informed ahead of time to make extra.

I stopped BIL and told him that the leftovers were for my wife and I, we didn’t make enough to send him home with leftovers. BIL got upset and threw (literally) the leftover prime rib back onto the cutting board that he had loaded onto the plate (which was all of it), pouted to his mom, and then stomped off to the car for the rest of the evening.

MIL husband left about 20 minutes later skipping opening presents to take BIL back to his apartment. My wife ended up getting an earful a few hours later from her mom saying that we were rude to not feed his caretakers and that they were expecting Christmas leftovers like years before.

I fired back (she was on speaker) and told her it’s not our responsibility to feed his caretakers when we were given no heads up beforehand. Had they mentioned something, we’d have gladly bought a larger prime rib and made extra food to send home with BIL, but since nobody said anything to us, we had no idea this was “a thing” in the first place.

MIL called my wife and I selfish AH’s and hung up the phone.

AITA for not sending our leftovers home with BIL for his caretakers?

UPDATE: my wife and I decided that it was a left over night. We planned on taking the left over prime rib, warming it up in gravy, and then smothering the herb infused mashed potatoes I made. Wife opened the fridge, grabbed the prime rib, then went for the mashed potatoes and gravy, only to realize it wasn’t in the fridge. She hollers over at me and asks if I ate them, I tell her nope.

Long story short: she texted her mom and asked if they took the mashed potatoes and gravy and she said yep. Her reasoning “just make more, you guys kept the prime rib so we took the mashed potatoes and gravy”.

I don’t care that they took the mashed potatoes and gravy, but the fact they didn’t ask, or say anything, is frustrating AF.