Welcome! Yes, this is a great place to talk about things you can't talk about elsewhere (when we're not too overrun with threads that are talking about US politics instead, sigh :-)
Did all the therapies and meds finally pay off? Is he just a late bloomer? I am assuming this score means that conceptually he understands 7th grade material. But how much could he actually do? And how did he learn two years of math in three months?
I don't know much about the MAP, but in general terms I guess it could be either or both - the therapies and meds paid off, and/or he's a late bloomer. Children learning two years of maths in three months does seem to be perfectly possible for some children - I'm tempted to say that it just shows how little maths there is in a school year, but that's clearly not a complete explanation! Anyway, it sounds as though things are going really well for your DS at the moment, and that's great.
The concrete reason you mention for retesting is understanding whether or not he has dyslexia; IIUC, an IQ test isn't going to do that for you. I guess that if his earlier score was an underestimate because of the 2e issues which he's now handling with greater ease, he might well get a much higher FSIQ this time - but if you don't specifically need that for something, I don't know if it would be worth the cost. Sounds as though his achievement may speak for itself at this point, which is a good position to be in.
