Are there areas he aces? Does he have some specialized learning he does for himself at home? You mention reading, writing, spelling as barriers. What about other areas? Is he just being measured by his weaknesses?
Great set of questions.
I'd also add-- is he "high average" in ability in those domains? Or does something about them seem "off" somehow relative to his verbal expression?
Some of that can be asynchrony, but if it's extreme, or if it just feels... wrong... then it's possible that there could be something under it, like dysgraphia. While his troubles may not be extreme enough-- yet-- to stand out to a teacher used to age-appropriate ability, if it's a major discontinuity with what feels like SHOULD be his writing ability, then that raises some red flags.
Dysgraphia and dyscalculia are often
very easily missed in high potential children until much later in their academic careers because they have so many awesome compensating skills that hide the underlying weaknesses.
