Rent, rent, rent. . . and then rent some more to find what he is comfortable with carrying and competent with shooting. Take the largest group size shot at any given range and double it. That will be roughly the size of shot group fired by a moderately trained individual at that range when stress is being introduced. If he can physically and logistically do this, try setting the gun on the firing bench(pointing in a safe direction) with the magazine out and slide forward with all applicable safeties on. Now back off about 25-75 yards and sprint to the gun. Load, make ready and engage the target as rapidly and effectively(safely) as he can. To add a bit more stress have his RSO/observer calling out the time as he is are working. Whatever weapon/ammo combination he hits with consistently and quickly would more than likely be the one to pick. And then after the fun of testing and buying is over take a course or two on the basics of pistol craft(malfunctions, reloads, retention, flashlight employment, use of force, use of cover), invest in range time and ammo, and always look for practical ways to improve your survivability. If you read through all of this, thank you for your time and attention.
