Without knowing specifics of the incident, I would suggest you not discount the possibility.
people get incredibly stupid when they panic, kids included, and there may not have been an immediate awareness of their family getting injured; and when your panicking and you don’t know how to handle a firearm, it’s not outside the realm of plausible that multiple shots get fired- even when we’re talking about adults.
I’m not saying the kid wasn’t abused. I’m not saying it wasn’t with some intent. I am saying there’s a not insignificant chance that the confession was the result of cops and detectives trained to extract confessions, by using some extremely manipulative methods, from a kid who is almost certainly scared and traumatized. traumatized whether he meant to do it or not.
FTA:
“We still got to put some puzzle pieces together,” the chief told ABC News. “The city can rest easy knowing that the suspect is off the street of a double homicide, but there’s also the shock factor.”