There was a part where Kurt says/thinks that the judgmental looks he is getting from the other boys is worse than the physical violence he was receiving at McKinley. He eventually quits the Warblers and becomes very depressed.
Something is said to Kurt, and in one of the final scenes he goes missing in Dalton. The Warblers look for him and they find him under a tree on his phone, crying/screaming to Burt.
I hope this is enough - it was a great fic! (I have already had a look around and it is NOT this fic)