I am looking for an historical explanation.
My brother wished to be a woman, and this caused great difficulty for him.
But why should it have? Not your brothers fault of course. But maybe the fault of the rest of us who haven't challenged the attitudes that provided those difficulties.
I imagine I have lived 99.9% as a woman, but then so have most males. Apart from public toilets, change rooms, sports teams and certain aspects of my sex life, there is nothing that I do that women don't also do.
I am wearing some trakky pants, a sloppy joe and sneakers. As quite a lot of women do.
When I wear a dress or a skirt, I am not trying to be or look like a woman. I am just wearing a dress or a skirt. They are often comfortable and some of them suit me. But I am just a male wearing a dress or a skirt.
I cook and wash up every day for my family. Quite a lot of men don't do that but there is no reason to think that is a masculine or feminine trait.
So for me to want to live any more as a woman than I already am it would involve me wanting to use different toilet and changing facilities and entering into categories in sport where I would have more chance of doing well.
But it doesn't really matter to me which facilities it uses and it matters to quite a lot of the people who use those facilities. And entering into less challenging sports categories would make sport less fun.
So for all intents and purposes I am living as a woman. And at the same time living as a man.
So if I were talking with your brother (and I am sad you have lost him, brothers are special) I would have said these things as I have said to quit a lot of the trans women I have met.
The big challenge is to get the rest of society to see it that way.
On autism and so on I am wondering why it exists only for humans.
I understand that atypical social responses occur in animals as well as repetitive behaviour. I don't know about other symptoms
I consider adhd a manufactured condition where people engaged in the wrong activities are medicated pointlessly.
I think you will find yourself wrong here. I have adhd, not diagnosed until adulthood. But I can look at my old report cards as well as old diary entries from school and see the clear symptoms of it showing through. I wrote something along the lines of "Why the hell can't I do my homework. I want to do it". I just couldn't understand why I couldn't even start the simple parts of my homework.
And the thing is that interventions, whether medical or not, do alleviate these symptoms. Some have suggested that I was just lazy an inattentive. Fine, if people want to describe it that way, but I didn't want to be lazy and inattentive and it affected my life, so if some medication helps me not to be lazy and inattentive then why wouldn't I take it?