I think that this song is about someone's lover suddenly committing suicide, especially because of the lines "Shame, such a beautiful, beautiful young life" and "Why did you have to go and leave all this stuff behind". The "Don't wake up won't wake up can't wake up, no don't wake me up" bit is about how the singer doesn't want to believe it's true. He kind of just wants to sleep forever to forget. When he says "How am I supposed to care" he is saying that if he is asleep, he'll be unconscious or "In the blissful unaware". I basically interpret the song as a story about MIKA's lover committing suicide while he was unaware (maybe while he was asleep because of the line, "It's the early morn, Lights flick on, Sleepy eyes peek through the blinds at something wrong, Motionless remains the mess") and he doesn't want to face the facts and believe it's true so he pretends that he's dreaming.
