To tell them not to bother coming for Xmas?

What bizarre behaviour by two grown adults. So childish to ridicule your daughter like that. I think you will be better off without them in your lives henceforth.

OP, Duty, Obligation and Guilt are difficult to cast aside but sometimes you just have to weigh up what makes you, and the people you genuinely love, happier.
Maybe your older brother can get through to your younger brother and you can connect again and help him cut the umbilical/apron strings.

Glad you have rescinded your invitation.
They sound awful.
I am sure you will get a horrible reply from them with a big dose of darvo in there so be prepared for that

And alcohol, chocolate, mince pies and of course cheese and I say that as someone who loves cheese so much that if there was a religion devoted to it, I'd sign up 😋🧀 But it's all the fault of the brazils, the pistachios, the almonds, the macademias etc...😁

Yes!
A huge parenting mistake for a child to be put in the position of having to defend his sibling against abusive relatives.
Unbelievable really.
So toxic.

From what you say its not about being vegan or not being vegan, its about feeling inadequate for some reason and attacking others for the imagined slight. Sometimes you can maintain a relationship particularly where there is a more vulnerable family member in the mix like a younger sibling, but there needs to be boundaries otherwise the balance could tip. It sounds like this was a tipping point. I wonder if your mother knows you tolerate her for the sake of her brother and has partly wanted the escalation so she could force a choice? I am sorry you have had to deal with this for so long. Holidays and other family events do increase the stressors on relationships perhaps this is also a contributory factor. She may back down but do insist on setting limits. I would be very clear that a family gathering is exactly that, people do not come to behave unkindly to any other guest present including a daughter or granddaughter.

Definitely keep them uninvited, they sound horrible. Just look at how many people you've got here siding with you when traditionally MN is rather negative about vegans! I'm not a vegan myself but have never had any problem with them and I wouldn't serve dinner to this pair even though it wouldn't make any practical difference to me at all.

My son told my mum and brother that they were out of line and went to check on my daughter. My mum and brother left.

you poor son having to step in instead of his parents to stand up to his awful grandmother.

how old is your DD and DS @WantToHibernate ?

I hope you went to HR. That is disgusting and indefensible behaviour.

DH has had friends take the piss, and once when we were invited to dinner (obviously the hostess knew he was veg) the wife set up a plate of raw veg in the kitchen away from the rest of us and said announced loudly in front of the assembled guests' If you are going to be a bloody vegetarian you can sit in the ktichen and eat your bloody carrots'. Unbelievable behaviour. It's funny how some people take being a vegetarian or vegan so personally, when it is literally not about them.

It's never from a place of concern. I think it's just something toxic people can latch on to and use to be nasty.
I've been vegan for years too. Most people just accept it - I don't preach, I don't try to make them eat vegan food, I just eat what I eat.
Some people though make a huge fuss about it. Who knows why. I just avoid them. They're not nice people.

At the bottom of the garden 🤔

Wow the cheek of your brother to firstly assume he is still invited to christmas dinner after that and secondly saying he doesn't want to sit near you or your daughter! He should just be grateful he is getting his dinner brought and cooked for him by someone else. I would definitely uninvite him for that, say you dont want to sit near me? Cool dont come at all, problem solved!

They sound like awful people. I would not have them in my house...

The fact that you are related to them does not mean you should have to see them if they can't show you and your family some respect.

"Don't worry, you won't be sitting anywhere near DD or me. We have decided, for the sake of a peace day, it would be better if you are not there. Have a lovely Christmas."

OP, well done on managing really difficult family circumstances and being a good parent yourself. That's a tricky path to navigate, especially when you have a younger brother in thrall to your mother.
Now it's time to look after yourself and your own family.

Tell them to piss off. I am a life long vegetarian (and great cook, even though I say so myself) and I'd be totally uninviting them, it's not like you became vegan to spite him.

When the majority of your kids have cut you off when why should that mother be given another chance? Just because she gave birth to you?

You reap what you sow with your kids and no, she doesn't deserve another chance just because she's the mother. With a bit of luck, the last son will see the light and leave her completely alone. Although from my experience, the youngest son tends to turn into his mother.

It happens more often than you'd think. I once had a colleague breathe in my face and announce that she'd just eaten veal. This was an adult professional woman.

I don't blame you at all for wanting to uninvite them, they are just plain rude.

However I would probably make one last attempt to tell them that they have no right to question the decisions of other people, they are ill informed, extremely ill-mannered and embarrassing.

If they are prepared to keep quiet about yours and your daughter's veganism, including not making rude noises and gestures, they are welcome.

See what they say and then make your final decision.

Most of us have difficult and embarrassing relatives but this is your mum and cutting her off would be a big step for anyone.

Personally I think people who have said to meet somewhere else so they can choose to eat meat are missing the point. They were rude and immature (refuse to sit beside the hosts in their own home. Grow up).
I'm vegan and my ex husband and I raised our daughter vegan. You would have thought from some peoples reactions we were feeding her vodka.
Some people interrogate you and then complain that you are going on about it. FFS we can't just live with our values.
My husband eats meat but he is respectful. He doesn't cook meat in the house though we have had words about him not wiping surfaces after preparing ham sandwiches.
The problem isn't you being vegan. If it wasn't this they would find something else to stir about. I have had to go no contact with some family members and believe me it's worth it. You don't have to put up with horrible behaviour from people just because they are related through blood or marriage.
Think about dropping them as dropping a massive weight off your shoulders and your daughters. You are setting her a good example for her to set boundaries and not put up with spiteful, nasty behaviour.

I'm really pleased you have binned them OP. I mentioned my mother's toxic family upthread. Basically what you have just displayed to your daughter is that you have her back, and her well-being comes first in the face of awful toxicity. She'll remember that. I am 52 and never really forgiven my mother throwing my father, my sister and I under the bus to appease her god-awful mother and sisters. She's actually apologised to us about it (this very year as it happens) and I've told her I understand- and i DO understand how enmeshed she was with her birth family- bit I can't get over the literally decades of misery we were put through all in the name of appeasement.

I wonder who the 1% are who think you're BU..

You've done the right thing. Enjoy your Christmas.

Dear Bro, After a moments consideration I have solved the seating problem to suit everybody . Hope you and Mum enjoy cooking and eating your Christmas dinner at home. We do have some presents for you, let me know a day/ time when they can be dropped off.

Sounds like binning them off with make your life better OP.

Have the row. It'll feel weird for a bit but it sounds as if you'll be better for it.

Book the local pub where they all pick their own menu. You can have the veggie options.