I would go ahead and give him a mental health day.
I gave my son a mental health day at least once a month (sometimes once a week) when he was in 4th & 5th grades.
A psychologist actually recommended it, after seeing his IQ and achievement results. My son had gotten progressively more depressed about school and said he never learned anything, and said it was just busy work that wasted his time. She agreed with him (well, his achievement test showed that to be true), and said that if he wanted to stay home and focus on a passion area, or to just take a break, it was fine. I tended to think that way anyway, but it helped to have a psychologist back me up.
