I think he won't (๑•ㅂ•)و✧ I believe that the blush and grin we saw on the last panel is the reaction he can't stop showing because he believes that Seyeong will be reciprocating his feelings (≧∀≦)
He's extremely socially awkward and not used to human interaction due to his numerous stays in hospitals because of his health. Calling him an asshole for that is exaggerated.
WHAT THE FUCK DO YOU MEAN "PERFECT ENDING"???????