For cognitive testing, the default should always be age norms, for which his grade level is irrelevant. Grade norms come up mainly when 1), a child has been retained, and 2), they are extremely young, and there is a concern about hitting the test ceiling. And these really only apply to achievement. 1 doesn't apply here, and 2 doesn't apply to the WJ. You should have them use age norms for both cog and ach.

...pronounced like the long vowel and first letter of the alphabet...