I don't know of any ranges in the DFW area that have a M&P 22 to rent?
I am not aware that the M&P 22 pistol is even shipping yet -- it certainly isn't in any reasonable numbers. S&W has shown the gun at trade shows, and it supposedly looks just like the regular M&P pistols, but does not have interchangeable backstraps and the fire control group is different as well. I have been very interested in seeing an example up close but so far no luck. I checked Davidson's and Buds online and neither have it in stock (Davidson's is a big distributor) so your chances of finding one to look at are pretty slim and even slimmer if you want to rent one.
As DA mentioned previously, we wanted a .22 pistol that operated just like one of the popular centerfire platforms, and the M&P .22 would be great since we already have M&Ps as EDC and fun guns. Since S&W has not released it in numbers, though, we looked at the following:
SIG Mosquito - slightly scaled down P226/P228, light recoil spring and mag spring (easy to load)
SIG 1911-22 - full size 1911 frame, light recoil spring and mag spring, manual of arms essentially the same as "regular" 1911, though stripping requires use of hex key. Rebranded GSG 1911 and uses the same mags.
Since it is full-size and has the same operation as a 1911, we chose the 1911-22, and have been quite happy with it. I would still like to get my hands on an M&P 22 when they are available, though.
BTW... there is an M&P 10 shot BB pistol (CO2) on the market that I have seen around for $50 or so. With a proper BB trap backstop it would make for a lot of fun even at home -- for you as well since you already have its centerfire counterpart. I have been having fun with BB/pellet guns for nearly 40 years since I was your son's age.