I am mildly frustrated with my brother and need to complain

It's basically a nothingburger of a post to be honest, I'm just feeling upset and I need to talk it out. Not gonna be surprised if that doesn't get posted after all.

I made a joke about Ralsei being saved by estrogen and referred to her with like she/they pronouns during our conversation. Bro got all weird about it, especially about me using she/her for Ralsei because "that's wrong and not supported by the text" (DESPITE THE FACT OF HIM REFERING TO KRISELLE AS HETEROSEXUAL AND USING HE/HIM FOR KRIS). I told him that I like that interpretation of the character and the evidence is convincing to me. Then he started texting me stuff like "you can't convince me that Ralsei is gay" and I genuinely had to block them after a conversation of me telling him that it's just a harmless theory and I just think it's compelling and adds depth to the character and him trying to "disprove" it by citing "he/him" and "prince" in relation to Ralsei as arguments.

And that person was open to hearing me out on kriselle knight (which I just thought was cool but I don't believe it since it's not as strong) and other weird theories, but as soon as I bring up trans women it's a justification to be an ads to me