Well, the tasks are visual-motor, but the directions still involve words. And he has to convert the words into a visual-motor task, which is probably the sticking point. The fluency tasks (all around, both on WISC and WJ) are also relatively isolated--that is, without meaningful context--which is even less suitable for high-verbal kids. The only fluency task that generally favors verbal kids is oral word fluency, especially if the prompt is a semantic category.

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