How wonderful that your son is an independent reader at this age!
We recommend the parent to read aloud all school books for children in grades 1-3 with the exception of a reader that he will read aloud to you. By reading aloud to him, you are able to read resources that are possibly written at a higher level than his current reading ability (providing him with a greater vocabulary, stretching his mind muscles). It is also a wonderful bonding time. These years fly by so quickly.
By requiring him to read aloud from 1 resource to you, you are making sure that he is reading slowly and carefully, not skipping words and pronouncing words properly.