My dear Albert, I suspect this is the bravest, most genuine self-disclosure comment I have ever read. I don't how to begin unpacking it, and likely it is impossible for me to do so. It could take life times to unpack all of this! There are a myriad tangential ways that could lead to better understanding and compassion for self and others in your narrative. May the few I offer here be minimally helpful.
My first thoughts had me wondering if brother was also abused. There is good evidence for generational abuse explaining trajectory, but doesn't negate the possibility of abuse being original to him. Hurting people hurt others is also a concept that has validity. Could being abused explain sufficient cognitive dissonance, or self loathing, sufficient to drive gender change? Gender dysphoria is real thing, no doubt. So is what used to be called multiple personality disorder, and people can have more than one gendered personality, and if one is dominant, does that explain gender dysphoria? Trauma opens the door for both of these.
But could it be even simpler; the cognitive dissonance of having harmed someone, family none the less, lead to cognitive dissonance severe enough to result in preferring another identity? Let's face it, in today's atmosphere men have been extremely chastised and blamed for all evil in society. Is the psychological need to become female predicated on not wanting to be the aggressor, in terms of perception or reality?
She may have changed gender, but that didn't cure your relationships with person because the offense transcends concept of identity. Even if person had simply been born against Christian, that doesn't necessarily absolve responsibility, or result in sufficient compensation to you to warrant forgiveness. And, hypothetically, if gender dysphoria is predicated on not wanting to be seen as 'bad' to any degree, then changing identity will not result in remedy because what is in the heart driving change remains in the heart; this may explain why post off-transgender doesn't see significant drops in suicide rates. Gender dysphoria has the highest suicide rates of all the disorders.
Your recognition of identity through country is actually well considered, metaphorical entry into this difficult reality. Just because you have claimed identity, doesn't mean there are not caveats that could result in expulsion from the 'group.' What human group is so inclusive that there is forgiveness for all transgressions? Can we be as understanding as God in terms of relationship to Cain? Just in metaphorical relationship to narrative parable, it is clear that though a soul isn't necessarily condemned to death, there are some acts that necessarily result in banishment, and or isolation.
Both you and your sibling are forever isolated from each other. In some ways, you both are isolated from the world and family you knew. You are both on a journey of self discovery with the hope of finding a group that will accept you. The fact that you were in a group, and then were not, will always leave in your mind the fear of a transgression, real or perceive, suddenly ejecting you back into the lone, cold night of being.
Your words are profound. I am emoting very strongly here, but I am grateful for your words and insight. Thank you.