The mood was dark as always, they couldn't stand being in the same room as him. They didn't bother to start conversation with the boy,  he would snap at them, hurt they feelings, maybe they should've dig into it, maybe they should've bring this up, maybe they could've stop him earlier. 

Kihyun was in bad mood, he was angry at himself, he had self esteem issues and no one noticed. He took his anger out on members so nobody even bothered. He was exhausted both physicaly and mentaly, he still cooked for the rest but didn't eat himself, they didn't noticed that.

First person who noticed was of course Hyungwoo, however only couple things, late vocalist practises, how restricted his voice sounded after many nights, that he wasn't sleeping but missed most important thing, self hatred. He didn't do anything about It,  they weren't even talking.
Wonho noticed how small he was eating, almost nothing and yet he didn't say anything about it. 
Minhyuk noticed sleep deprivation and crying at nights, he didn't confront Kihyun. 
Jooheon noticed how he wasn't smiling anymore, how dull his eyes were.
Hyungwon noticed at dance practise, how exhausted he looked, how he couldn't keep up with them.
Changkyun noticed how weak he was, how skinny he got, that he looked like he could faint any moment.

They ignored it for about month until one night they couldn't anymore. Kihyun collapsed at they way to the dorm and they didn't know why. The big dark bags under his eyes could be reason or maybe how skinny he got, how pale his skin was, how lifeless he looked. The biggest scare was when they checked his breathing and they couldn"t feel anything. Hoseok imidiatly called 911 while Minhyuk began CPR. When the paramedics came he still wasn't breathing. The rest were scared less, Nothing could have prepared them for what doctor had said.