I'm assuming you couldn't have swapped it anyway from the comments. If you could have swapped it, it would have been a nice gesture, and if I weren't disabled and had a 6'6 brother one I'd probably offer. The MINUTE it was assumed I'd just be giving it up though that would be it. It's not his right, it would be a thoughtful sacrifice of something you've earned (by having to spend money to sit in a flying tin can for hours on end).

I would have take the first flight back home and go no contact with the family. I cannot stand passive aggressive cowards and their enablers.

Him asking for the seat and her refusing, and then him continually asking, is begging. Him not even asking isn't begging, it's expecting OP to give the seat to him without asking

Being upset in the five minute conversation after landing is normal. Getting pi$$y and passive aggressive for a week is a display of emotional infantilism.

NTA. To put it crazy, as said, the first class upgrade can not be transferred. I fly alot, both business and personal. All my business trips are paid by my employer. We went to a seminar with a few other coworkers. I was offered an upgrade and my boss had a freak. Saying he paid for my travel. He should get it. I agreed and told the flight attendance that was fine. We were told I was only being offered the upgrade because they needed the coach seat for a standby customer. And I may not save my upgrade for future flights or transfer the upgrade. Needless to say my coworkers and manager was quite unhappy. When we got back to home base, the animosity was too much and I quit. My points was a combination of business and personal. It wasn't separate. A free upgrade that was now or never, and couldn't be transferred? Sorry boss.

I hope an update comes after OP shares this with her family. Or throws the facts at them. Shoot, I have a pinched nerve in my back that rarely acts up, but when it does I use a cane. Went to Disneyland with family and I had to use the cane by day two. And I usually refused to skip ahead in lines whenever I was asked because it's not like I'm completely disabled. I have a feeling if this family had the same issue, they'd all be demanding to jump in front of everyone. (P.S. I did accept the jump ahead a few times when the lines weren't all that long, but partly because a few of the other guests would tell me to go ahead. Hey, I'm nice, but who am I to refuse someone a good deed for the day? Lol)

Fück your family! Or, rather, don't, there's already enough of them...

*facepalm* I hate how people who don't fly frequently/consistently are the ones that complain the most. (In this case the brother). Even if OP wanted to be nice, a majority of US airlines won't let you do this... even if you have the most loyalty on the flight. Why? Because us loyalty folks know how the system works. Flight attendants will not risk confirmation and /or complaints to upper management for upgrading out of order of loyalty rank let alone someone with no loyalty status

It's a privilege not an entitlement,if they are all bitter about it and making the holiday awful, I'd apologise to my father for ending the trip early ,just reimburse the flight amount. I'd leave them feeling bad for ruining the holidays over something like this then meet them less.If a family is this selfish then there's no need for them to be near you

The seat could have gone to him if she switched after takeoff. But the expectation by her family that her first thought should be the comfort and convenience of her brother over her own is odd. I bet the family has a pattern of putting him first.

Wow entitlement doesn't quite cover this. 1 they offered it to you not your brother. They could see he was tall. Did they offer for one of your family members to take your place. Nope it was how many points you and you alone had. 2 if he had been a grown up man he could have asked hey if we can can we trade. He didn't do that. 3 like every body has been saying he could have paid for a seat with more room or they could have. They knew how tall he was. Tell them to buy him a first class seat home. Nobody will step up. Yes he was uncomfortable boo hoo you're going to Hawaii grow up everyone. Honestly have the airline explain it if they are huffy still. And what the hell is the dig with your niece and nephew. They all need to grow up. Especially the sister with they only like to play with people who consider family. Read her go no contact except for dad tell him your happy for him. Seriously grow àss people acting like children. Hope sister sees this. I'm just as big a bìtch as she is.

She's going to end up family-less if she follows the redditer advice to blow everyone off. She should at minimum lie that it was non transferable. I don't think most people understand how absolutely gargantuanly tall 6'6" is and how it makes everything in life horribly inconvenient and quite often painful.

Maybe, if it were allowed by the airline, you could have swapped halfway, so that you both got a first class upgrade. Otherwise, I agree, NTA

Did a 12 year old write this?

No, she was not being a jerk. Her family is full of A holes. I would Tell them to screw off and then leave

Why did her family think that the male child should get the better seat?