I come from the camp that everyone can use more instruction/thought in their reading skills.

Can he discuss the books he reads? Can he synthesize material? Can he make inferences, and harder for young kids, inferences about the motivations of characters? I'd go for whatever skills he does not have in place and take aim at that.

As for getting it done in the school - this level of differentiation takes teacher time or peers or both. It's hard. I spent 5 years discussing books with DD before school was able to take up these skills.