... Some rudimentary home defense training and an operational plan could have reduced the risk.
...
The kid moved his siblings to a more secure location and took up a defensive position between them and the threat. That's pretty close to my own operational plan. The fact that he hit the bad guy with one shot while under stress would lean more toward him having some training than against it.
More planning and training might have been better, but I see no indication that there was none.