[jet]

Gary has no inkling what to do with him because he isn't a real artist who 'feels' songs and knows where he wants to go. It isn't the song choice that's the problem, it's how they are sung, interpreted and 'felt'. Gary can't perform the songs for him.
Chris could easily refuse to sing a song if he felt it wasn't right for him.
I feel Gary can't stand the guy and has been doing an admirable job keeping a lid on his feelings.