Responses
I kind of understand him from experience. When you think you did something terrible to someone else it makes you feel kind of paranoid about it happening again. Even if you barely knew them, you can't help but feel guilty. So instead of saying what's on your mind, you just try to be as nice as you can because you don't want to hurt someone's feelings again. Yes, he didn't know her but you don't have to be friends with someone to care.
( ̄へ ̄)
I'm sorry not really trying to invalidate feelings here but I expected more on the reason why he closed himself off :/
He's not even friends with the outcast girl nor have any relationship with her to begin with. It doesn't make any sense :v