We've been playing the game with the letters. Not ds' strongest suit(!), although he immediately cottoned onto the fact that he didn't want to go first as then he could simply add prefixes onto whatever word someone else came up with!!
Welcome home!
Hope you had fun while playing that little game, making it fun is right where you need to be right now. Good for him and his fluid reasoning for figuring out the prefix trick. Even that is good for mental-muscle flexing, afterall, one can't just stick a un- in front of every word, so eventually he'll use up all the prefixes. As he gets stronger at it, you can try insisting that he go first 1/5th of the time, etc.
Try the other tricks, take notes (secretely) and let us know how they went - we'll come up with more ideas to tease out what is going on.
I really don't know anything about dyslexia, but it sounds like it's worth a try to contact several folks who help kids with dyslexia to take a look at him and teach you what they know. I would suggest that you plan to talk to 3 before you even thing about if you should hire one to work with regularly. If you are lucky, one of them will be flexible enough to see that a kid with a super high IQ can still have dyslexia.
For now though, see what the developmental op says and decide to work with her/him or not and keep working those strengths!
Smiles,
Grinity
