"I can never imagine him being in a relationship with a human" 

Kibum started the so called 'Jinki talk' yet again, out of nowhere. Jonghyun usually  doesn't have to mention Jinki, or even recall his high school memories for Kibum to commence the 'Jinki talk'. Sometimes Jonghyun regrets all of it. He regrets everything from giving a damn about Kibum's grades to contacting his friend from high school to tutor his arrogant but sassy younger brother. 

"just shut up Kibum. We don't need to have that talk today"

"Oh-come-on, I mean- Isn't he your friend? Aren't you worried? He doesn't have a life dude! And you do know that I don't hangout with lifeless humans, right? You should under."-

"FOR CHRIST'S SAKE KIBUM SHUT UP!"

And that was apparently powerful enough,not just to shut Kibum down, but also to shove him away from the kitchen. 

Jonghyun and Kibum are like oil and water. They're completely different, yet exist together as brothers. They have kind of a peaceful ,mild relationship. They aren't too much friendly, but they rarely fight. Of course both of them would give their lives for each other, well, literally. But they don't interact much,given their complete different personalities and complete different interests. 
Jonghyun continued sipping his tea peacefully. 

Lee Jinki..
Jinki and Jonghyun were friends in highschool. They were both smart, good at scoring in exams,but, Jonghyun was different from Jinki. While Jinki was considered as a nerd Jonghyun was considered as the icon of his class. His grades were beyond perfect just like Jinki, but what made him different was him being the multi-talented legend of the shool.He was in the school choir, and despite of his short height he managed to shine brightly as a striker in the school volleyball team. Not only that,he was their in the swimming club and he was a part of the relay team. 

Jonghyun didn't know much about Jinki. But he knew that Jinki was having a hard time back then with his family finance,which was kinda obvious and which was,of course ,public information at his school.  Apart from that they weren't that close. They've interacted with each other only regarded to subject matters.
When Kibum's Math and Science hit a wall last semester, without even a bit of persuading from their mother Jonghyun decided to contact his highschool mates on his own will. He was unable to tutor his own brother Because,
1.that would be utterly impossible. Jonghyun and Kibum had a mild relationship but Kibum wouldn't consider it serious.
2. Jonghyun doesn't has time. Just like he was in high school he's there in the college athletics.
3. Jonghyun doesn't like teaching.
Minho was his athletic buddy from high school and fortunately he had contact details of Jinki whom is tutoring high schoolers as a part timer.

Even after Jinki started tutoring Kibum Jonghyun didn't had a time to have a quality conversation with Jinki.

Kibum ,on the other hand , doesn't want his brother to be dissapointed with him. But it's Jinki- that Lee Jinki. How can someone put up with him? Kibum bears everything, he keeps his mouth shut, he literally steps on his own spirit while he is in front of Jinki. He doesn't complain about his weird