My DS6 also had great fine motor skills and pattern recognition. My dad made wooden alphabet and number puzzles for him, and that's how he learned his letters and numbers well before he was 18 mos. He LOVED those puzzles, wanted to do nothing else all day but those letter and number puzzles, obsessed over them for months!
If you can find some wooden letter puzzles, it might be just the thing for your child, too. You can start spelling words for him with them as he's ready for that, too, and pointing out that the words you spell with the letters are the same as the ones in his books.
As a side note, our pattern lover was ready to read early, since language is just another pattern to recognize. Be aware that yours might be, too.
They're all different, of course, but your son sounds so much like mine, I hope maybe this helps you!
