On September 23, Kim Kibum's birthday, his grandmother, the one who practically raised him, passed away. It wasn't until today, October 5th, that he decided to tell the fans on instgram(?). That was the reason he wasn't there at the concert on September 24th. 

Let's give lots of love and support to Key and SHINee during this rough time.

Rest in peace grandma Kim

<3

Luci~<333