Good for the boy. It just goes to show that mindset to not be a victim is paramount. However, hopefully mom will buy a pump action shotgun and show him how to use it.
Mas Ayoob tells a story of a friend who would oil his revolver liberally - like dripping in oil. One day he was on the subway and gets attacked by a guy. He drew his revolver, and pulled the trigger, and click. The oil had soaked the primers and made them useless. However, upon hearing the click, the bad guy's eyes rolled up in his head and he fainted. :)
Sometimes we get lucky, but we shouldn't plan on it.