Actually if hit in the chest by an object, over the heart, in between beats the heart will stop. This has happened with basketballs and soccer balls and baseballs hitting a person, also a punch thrown at a persons chest can also have the same effect. More than likely this is what happened and if CPR had been administered immediately the kid probably would not have died.
Think I need a refresher on my CPR. Most EMTs tell me that it really does no good for a heart attack. With such a young victim maybe it would have been successful. Will never know. Having done equally stupid things in my youth, its a there but for the grace of God go I sort of thing. Prayers up for kid and his family.
I have on purpose hit a person hard, in the chest with the ball of my fist....to take them out of V-Tach. Also, just asked an alert person to just cough hard...and that took them out of a run of V-Tach too............
fwiw-
I'm guessing that CPR would not have mattered at that point. A six pound object at a decent velocity is 'blunt force trauma' -- the kind that can crush heart tissue or split the aorta. That is far worse than a line drive or a punch that can knock the heart out of rhythm.