From Wikipedia’s entry on Coldplay’s Fix You:

Some sources claim that this song was written for Gwyneth Paltrow by her husband Chris Martin due to the depression she suffered after the death of her father Bruce Paltrow. Other sources say that the song was written about the time Chris‘ dog had to go to the vet.

Didn’t realize “fix” would be so literal.

“Tears stream down your face when you lose something you cannot replace,” indeed.