Well, ultimately, we want to store useful things in long-term memory, so his efficiency in this regard is, in the big picture, much more useful and important than any minor inefficiencies in working memory, especially since he seems to have good retrieval, from what you are saying. Where you might see some impact would be if you ask him to multi-task, or follow a long series of directions without visual aids. Especially outside of a meaningful context.

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