Responses
*CLOSURE I'M SORRY FOR THE TYPO
I think because it is so healthy and short. It's pretty straight-forward, so unexciting. Also, I think Kyouji called his twin with the hopes of getting Sonoda and his sempai back together. I don't think he realized that Sonoda loved him at all, just wanted temptation to be taken away before things got messy.
Talking about the healthy (?) closeure the older Matsumoto twin and Sonoda had? In order to move on, —and for his own sanity— Kyouji Matsumoto called for his twin, to talk things out with Sonoda. Older Matsumoto was nice and gentle, yes, and he even goes so far as entrusting Kyouji to Sonoda, which furthers their path to separation, and thus, growing up without the guilt from their rocky past.