Felony murder - http://dictionary.law.com/Default.aspx?selected=741
It wasn't simple shoplifting, it became a robbery, which is the requisite felony, when he struggled with the man. There is a distinction under the law. Maybe the kid was punching and kicking him, maybe not. Clearly, a robbery falls under the felony murder doctrine and the prosecution is right charging him with murder. He'll most likely be offered a plea deal that won't include serious prison time.
Additionally the Penal Code in CA explicitly states it is not designed for rehabilitation, it is designed for punishment. If he needs a road map he should have committed felony murder in a state that rehabs criminals.