According to news reports the weapon being used by the 8 year boy was a micro Uzi.

http://uk.youtube.com/watch?v=0k6y8VOjOhc

Judging from this video the weapon appears to have has a nasty tendacy to pull up even when an adult is using the weapon. If the stock isn't correctly deployed or the stock slips from the shoulder due to recoil then I suspect this weapon would easily rotate especially in the hands of a child.

The father was apparently 10 feet away attempting to take some photographs or video. Youtube is full of videos showing very young children firing extremely powerful weapons.

http://uk.youtube.com/watch?v=sgioghA1QEc&feature=related

And yes there are videos of very young children firing full automatic Uzi's while the photographer is in the front right quarter taking the video eek.

http://uk.youtube.com/watch?v=s6BV8P0nNas&feature=related

So I guess this type of story doesn't really surprise me.