Apparently his 7 year old stepsister was likewise not confused or upset about the fact that a shotgun blast had just gone off inside her home, since she just hopped on the school bus too, and the police didn’t get notified until the tree trimmers called from the house. There are clearly a LOT of missing pieces to this story.
Why would anyone point blame at the 7yo girl? She’s not a suspect. If she knew that the boy had shot her mother, and she got onto the bus, too, then maybe some psychological help is in order. But, she’s not a suspect in this case.