Its probally just because he is tired, if you guys are fine in the afternoons then dont worry about it
It's a simile. It is also an oxymoron, with the idea of loud quiet (the noun quiet modified by the adjective loud).
quiet for us.
loud
Quiet Is the New Loud was created on 2001-03-06.
Quiet Mouth Loud Hands was created in 2007.
Antonyms for the word loud: inaudible, low, quiet, soft, subdued
it is loud
quiet.
loud
Quiet and nonspoken
Loud. Ya bass...
loud