I also suggest a full neurosyc workup if you can figure out a way to get one done. My two kids both have language processing disorders with varying degrees. DS16's (my gifted child) is only expressive language. While my older DD was diagnosed with an LD in language processing and struggles with both reading & writing. She would do what you describe as skipping/replacing small words and her comprehension was very poor. (Neither kid has handwriting issues.) But her decoding skills were right on grade level. DS on the other hand seemed to do great until 6th grade when he started to get 'stuck' when trying to write essays and didn't understand how to get the information in his brain out on paper. Evaluation and working with trained professionals have helped. It was a bit startling to realize my second child who seemed so advanced at a young age had some of the same challenges his sister did.
I have one suggestion for working with comprehension that comes from the professional who I hired to work with my daughter. Comprehension is best worked on with short non-fiction texts. Articles from a newspaper or magazine, 1-3 paragraphs taken from larger text. (These texts can then be at the child's reading level.) Non-fiction tends to be more concrete.
Have your son read fiction books at a level his is comfortable and work up. Clearly he is not ready for a book with too many pages without pictures so I'd back off on that until he is ready. It's just going to turn him off reading.
Last edited by bluemagic; 10/28/15 12:58 PM.