I think they're (maybe unofficially) dating. The conversations in this chapter seemed like someone who recently started dating. I mean he freely said she's cute and other stuff.
Idk whats worst... he thinking is normal to say to her that her breasts are cute as always or how what he just said somehow didnt result in a proportional progression/development.
Guess, I should give up and wait the author get tired of the push & pull sketch with this 2.