It doesn't really say much about what happened other than the son was hit by the tire. I just hope for the sake of the father he wasn't doing something really stupid or had a few too many and decided it was a good time to fix the tire. Something like having your son die that way would be hard enough.
Don't know if it was a split rim but they are a pain. I've changed several without a cage (I just fill them using a remote valve). The wheels rust and the rubber sticks to the rust making them come apart hard. It's easy to damage the ring while trying to break the bead. Secondly once apart you need to remove all the rust to make sure nothing will hold the ring from seating into it's groove. Finally if the groove or ring is rusted too much it may not lock and you are better off tossing them. To change one is a lot of work, I can see tire shops just refusing to do it.