I know him from school, and I was more or less acquainted with him, but with school being closed for the past year I haven’t talked to him at all.
I just looked and his online accounts all have anime profile pictures and “she/her” listed. I don’t even know what to expect the next time I see him in real life, which I assume will be this September.
No he didn't. He's still a man. Nothing he does will change that. Words have meaning. Don't let them corrupt knowledge.
While I agree with your premise, I think it would only apply if he said “become a woman”. He said become “trans”, which is right. Otherwise I don’t know what word we’d use to describe this. .02