Does he seem 'age appropriate' in his general conversation level? When he talks about his favorite book/toy/TV show does he seem to have more insight than average kids his age? What is his vocabulary like?
A book I'm currently reading about how to teach reading comprehension you might find interesting:
'Strategies That Work: Teaching Comprehension for Understanding and Engagement' by Stephanie Harvey and Anne Goudvis
One thing to try is to read through this book and start spending some of your one on one time with your son talking about ideas - poems, song lyrics, picture books, audio books, so that his thinking about words can soar ahead if his decoding is holding him up.
Remember that an IQ test can confirm what you suspect, but it can also be a poor reflection of your child. See for yourself if you think your child's vocabulary, understanding of word-ideas, and general knowledge is average or above average.
In the meanwhile, be sure to provide as much chance for him to use that Perceptual reasoning skill as possible.
Love and More Love,
Grinity
