Our recent discussion about the Torah/Talmud and Biblical texts reflects the difference between the religious retributive justice and our own U.S. premise of restorative justice, from the English common law tradition. It argues not only against a belief in any God given right regarding weapons, it argues against abuses of the judicial process like this.
What this boy did is horrible; what his mother did is, in my opinion far, far worse. I question the capacity for this boy to understand the right and wrong of what he was doign adequately to construe it as murder, and his capacity to have adequate intent to do so. It is a miscarriage of justice for him to be tried for murder.
On the other hand, while his mother did not commit the originating injury, she is the one responsible for it being a fatal injury, not her 12 year old son.