The article seems to suggest that he was shot again whilst on the phone to 911. If that is true, it looks like was indeed murdered. Otherwise, it would have been easy to speculate that she did it in self-defence against her drug-crazed and violent grandson.
There are plenty of stories from when it happened that pretty clearly suggest that granny had reason to fear. Police had been called to the house before for domestic violence.
I don’t think grandmothers are equipped to handle the juniville delinquent teen grandkids as they are abandoned by their failure face parents. I don’t intend to say that shooting feral family members is okay.
I would be interested to know about this kid and his interaction with granny. Why wasn’t he living with his parents?