Forget diagnosis for a minute, if you know my ds'.
He reads apparently fluently unless you read over his shoulder and see that he is still getting the meaning across but with entirely different words to what is on the page.
Often the meaning is plausible though entirely at odds with what is actually written.
So he might read 'Mike looks a lot like his Monkey', as 'Mike looks a lot at his monkey'.
Due to these mistakes I'm thinking his comprehension isn't quite as bad as everyone seems to insist as his sentence often makes more sense (As in the example), but it isn't right.
Any ideas?