My formerly estranged brother has transitioned and wants back in mine and my mother’s lives.

I have to agree. I find it hard to imagine a mother so uncaring towards their child that they would only be nice and welcome a relationship with them due to societal pressure rather than parental instinct.

Hi OP
it may have been mentioned elsewhere but I’m worried your brother may wish for involvement with your children in an ‘aunty’ role. I have not experienced a transitioning brother but I’ve certainly experienced a callous one. To have any contact with them- eg at my mum’s, Christmas etc- I had rehearsed exit lines, plans with my DH and boundaries I would not allow to be crossed. And I would always have an exit strategy.

But before any of that I had to decide whether I wanted contact. In my case, I did.

In your case - well it’s all on his terms isn’t it? You haven’t decided you want to see him again… he has. And why? To apologise for his previous behaviour? To make amends and heal relationships? No. Its to show off his shiny new identity and watch you all squirm as he rubs it in your face and your children’s faces.
His gender may have changed but his character hasn’t. Stay well away.

well I have been told by the Op that I’m absolutely wrong!!

He'll still be a horrible person as a transvestite.
I'd keep well away from him.

I deal with this by adopting a persona. I don't say anything that will trigger them, I don't engage or get pulled in, and I keep my thoughts to myself unless they are going to be helpful and well received. I basically keep the peace, regardless of what I think privately. So there's distance there but I don't think they notice it, though I expect others do who know me well as they can see I'm far more reserved when they are around. I lie by omission and I'm ok with that.
I see absolutely no point in engaging in opinions as we're pretty much at opposite ends regarding transitioning and we'd never agree, I do firmly believe that people can dress and present however they want and I will call a person by their chosen name. I avoid pronouns like the plague. I've no interest in drama, and I know my relative loves drama and actively looks for opportunities to create.
I've been supporting my elderly parents because they went into this with open hearts and arms but without planning for how this could go, given that they know this person of old and this leopard has only changed his dress, not his spots. They get very upset if they think, or are told, that they've said or done the wrong thing. It's really hard, I hate seeing them agonising over what they could do differently when there's nothing, simply because the person is looking for issues and will make an issue even if nothing actually crops up.
I wish I'd had more of a frank discussion early on about how they could deal with this and that they have some choices, and to hold in their minds how they dealt with this person previously. They are wrong footed and upset after every interaction, but this is because my relative is quite combative and is actively looking for offense or 'wrong words', iyswim. So my role is basically to calm them down and put some perspective in and comfort really. I think this will eventually settle down, I hope so anyway.
I definitely would not allow access to the kids, but equally I wouldn't miss out on family occasions to prevent it. My nieces are told that our relative just likes wearing what he wears and that's fine, and we use only his chosen name, never pronouns, and he's not given a title either (it would be uncle, he'd prefer aunt), name only. And their parents just limit any direct contact when the family is together, opposite sides of the room, only a few mins chat etc. They've not announced anything to the rest of the family, but it's pretty apparent what they are doing and I think they've had a quiet word with a few of the wider family who might otherwise have gone big on the 'oo here's your aunty' type of chat with the kids. The kids are too young for a frank discussion of the ins and outs of trans people.

In supporting your mum, I would think also about what support you are willing to offer outside of what your relationship with your brother looks like.

For example, if every time you meet up with her she is telling you all about what he is doing, or offloading about unreasonable stuff that he is doing/saying what do you want to do?

I personally have a very low limit on hearing about the latest drama in my step-brother's life and keep any chat about him and my step-dad very superficial. Not my circus, not my monkeys.

Of course, women should only be seen and not heard.

Surely you quite simply say you stopped contact for xyz reasons/ behaviours. That hasnt changed, they still did those things. You do not want to reinstate contact. What your mum does is up to her. Transitioning or not makes zero difference.

@Rimding

Sorry if i missed it but I don't get it.

You are NC.
Presumably neither of you wanted a relationship for whatever reason.
That status quo was maintained for a long time.

Just because your brother suddenly wants contact now doesnt mean you have to agree to it.

He couldnt be bothered to get in touch when your father died....why now?

Personally I'd stay NC let your mum crack on if thats what she wants

In other words it's the same person, just with a bit of lippy on.

Support needs to go both ways, and backing your mother into a corner buy putting pressure on her and requiring her to accept and validate that her son (says he) is now her daughter is not what I would call particularly supportive of her, is it. How long ago did her husband die? Is she vulnerable at present, and might that be a reason suddenly to decide to coerce her back into his life?

So the fact she’s his mother and happy they’re are back in contact is also a factor

You have been estranged for years…. Something pretty awful must have gone down in the past. So yes - just keep at arm’s length if he does indeed decide to go further than just mention to his mum that he’d like to start up a relationship again

Presumably because the OP has discussed it with her mother, as she said.

Why would you think you know better than the actual people involved? OP’s mother is presumably allowed to speak for herself.

What your brother is doing sounds mighty like some of the shit my brother does sometimes. I wouldn't worry too much, OP. Just keep your distance and before you know it, he'll piss off again for some reason or other only known to him.

Hi Op.

You are already estranged for good reasons, unrelated to trans issues. These issues may not have changed so think about what you are prepared to go through again, esp as you have children. If someone is so abusive or difficult that a relationship has ended it is only worth rebuilding if it is healthy and not coercive. Your brother's feelings are not the only ones that matter.

It is especially cruel of your brother to try and line up your wider family and coerce your mum (and I assume you) to submit to his fantasies about being a woman and have contact with him. You mum will never forget the son she has given birth to and this is an element of cruelty that raises red flags for me. Wider family will not be so strongly impacted.

links for relatives of people who ID as trans

-If you want to chat options through with other non judgemental adult siblings on a private group online this link is helpful.
https://genspect.org/support/
I believe that Emma (link here) facilitates one of the groups but not sure who else does.
https://childrenoftransitioners.org/about/

-Re potential impact on your children you may find this helpful ,written by children of transitioners with a variety of experiences good and bad - not siblings.
https://childrenoftransitioners.org/

-There is a film of interviews with female partners of men who Id as women called Behind the Looking glass (free on youtube)

I wish you all the best whatever you decide.. xx

I would do everything in my power to keep him far, far away from me and my kids, if I were you, especially since you say he has also behaved callously in the past.

Ah okay....

As someone with experience of NC in immediate family.
I'd just say no for now..

Let your mum proceed and see how it pans out...theres nothing stopping you from changing your mind in 6 months.

Did he come to the funeral? I slightly assume not, because if he had, his transness would have been known from that moment on.

Honestly, this stinks to heaven as far as I am concerned. Whatever else, he is showing no empathy for your poor mother when he adds another lot of pressure on her when she has enough already.

Does he really? Or does he want you to validate his life as a 'female'?

If he's been callous and uncaring before, I'd suspect he wants you and your children as props in his own life to make him believe his own view that he's a woman now - no matter what he knows, very deep down in his heart.

Putting the transition to one side. If you have been estranged from your sibling and therefore NC, then there was obviously a reason behind it; likely a combination of several incidents over time.

While your sibling may want a relationship with you, you don't have to concede. You do not have to have a relationship with them if you don't want to.

I can't imagine a strictly civil relationship that requires any discussion, or even passing mention of your different beliefs. You can exist in the same familial spaces without really interacting at all - it's what some of my family do. If they've changed their name, fine you can refer to them only by the new name.

But I think that is focusing on the wrong thing. If you don't want to have a relationship with them then you are not obligated to. If your mother is as susceptible to outside pressures as you've suggested then she will surely be susceptible to your pressure to keep you out of it.