Definitely on the mark with the "test before trust" methodology. I've seen several examples over the years even of folks that new how to "behave" at the range under the strict rules, but were reckless out in the field environment. One of my favorite ways of testing is to take them out on pellet rifle hunting in the field first and use that as a testing ground to watch their handling, proper use of safety switch, loading, unloading, etc. At least then any accidents are not quite so damaging, and at least give me time to slap some sense into them and take it away easier. lol. Reckless people are often reckless people, whether it be driving a car, using a knife, towing a trailer, blasting fireworks, or motorcycle. No different when it comes to firearms.
My thoughts exactly, the reckless people thing; it tends to be a habit.
When it comes to firearms, well I don't need to tell you I guess, an extra level of attention is required. I like your pellet gun thing although all mine are centre fire rifles. I expect this guy to be safe and responsible or I'd not be entertaining the thought of taking him but it needs to be verified as you know. I think my only he shoots plan should work. I can see how he handles the firearm, where he points the muzzle, trigger discipline etc.
I never use the safety prefering to close the bolt, pull the trigger, and then load the magazine which leaves no chance of an accidental discharge. When a target presents itself it's easy enough to rack the bolt and shoot quickly. I will ask him to do the same.
We'll see how it goes. I think he'll be fine and it might be good to have company from time to time.