So even if you were to take the "We're like brother and sister" stuff at face value, ain't no way Chieri actually convinced herself she's the older sibling in the dynamic. lol
It's been a thing for a couple of years now with more schools in Japan have been adopting Gender Neutral uniform options for students because its been a popular request with the youth.
Still kind of a dick move on his part. Like nice he's giving a peptalk but he's still treating them like characters in his favorite story instead of actual people in a world he's living in now.
He was delinquent growing up and it compounded on the fact that his parents considered him a lost cause and started to emotionally neglect him in favor of his younger brother.
Flip side of that is all the adoration on the younger brother put insane pressure on him so it was just two-sides of...
We call them Parasocial Andies. They believe they have a close personal relationship with their favorite internet personality and take things like this that has nothing to do with them as a personal slight.