Sorry I missed your post. Teaching a kid to have a healthy dose of skepticism is a valuable lesson...
I told him every gun after that will seem tame.
After the .50 in the video he took me aside and said "Thanks for pushing me to shoot that thing, it was awesome, your right it wasn't that bad and it would have bothered me for the rest of my life if I didn't shoot it"
He shoots my M14, nagant carbine even the grizzly 8.5 without issue now and loves it. Pretty good shot actually.
Next is driving, but not just driving. Driving on a 400 series highway with a near flare tire and drunk.
After that it's how to deal with women