Responses
Also kinda of a spoiler,
Felix finds out their brothers, but at first he thought they were kissing since Leegang doesn't understand personal space.
Also I translated the last panel from the raws and in chapter 128, there is something like a rumor going around that the president of the company ( Felix's Dad ) has a son which is Felix.
I THINK I can explain since some of you are confused.
1).Gio was born in Korea and was in the orphanage from around the age of 5 & 6 (around the same time Gio met 3 yr old Felix).
2).Gio was adopted by his family probably around age 6 and they moved to the USA.
3).Based on the raws Gio was put in the orphanage for his illness by someone I think is his biological grandma and she's looks rich, sooo... By the Google translate comments she called him defective.
4) By what I saw He goes back to Korea and the story starts when he is already settled in Korea.
5).The reason why everyone probably thinks Gio is Leegang's brother( younger brother since Gio is 32 and Leegang is 28) is probably because of the picture of Gio on Leegang's mother's bed table. And also because they look alike because Leegang's father in the raws looks like Gio and he has the same mannerisms as him.
6).Felix's mother and Leegang's (and probably Gio's) mother were friends in high school ( and I don't think they were together or are going to be together but I'm not fully sure).
7). Noah ( Gio and Leo's childhood friend ) and Leo ( Gio's adopted brother ) seem to like each other or are together and are having a fight or something in the raws So, side ship, I guess.
8).Felix and Gio have nice sex and Felix either gets fingered or spanked.And by the Google translate comments Gio gets turned on by Felix calling him General Manager.
9.Felix's mother accepts them from what I saw in the raws. Since they were talking and Felix was blushing.