Okkkk so I read the raws for this, and I thought... isn't this just a gayer, set in Japan, slightly watered down version of The Kite Runner? Here are the parallels...
-rapey vibes
-one of the MCs are plagued with guilt after childhood incedent
-shady alley
-buff manlyman dad
-dead mom
-kids live together
-atone for sins by taking care of some other character
-one MC is pure and kind to everyone while the other is troubled
Hmmmmmmm
Except MC does not appear as innocent as you seem to think even from the first chapter.
First things first his mom should've just taken him to a therapist instead of setting him up with a blind date