This story made my heart jump into my throat. I am SO glad he is relatively unscathed. I will be thinking of him and wishing him a speedy recovery.
I have two teenage boys, and I cannot express how much I can envision something like this happening. They just don't THINK before they do things sometimes, and this is NOT your fault. They do things on impulse, and that part of the brain is actually the last to mature (into their 20's). It scares me senseless that this could easily have been my boys - this and countless other "stupid" things. I'm half holding my breath until they're 30!