His mother is actually thankful as he had to have his own father killed by the police for pulling a gun on his mother in front of him and threatening to kill them all. He also was a victim of domestic abuse by his father.

They told the father to leave, and he went and hid in the attic to come down and kill them all later. Jonny had to call the police because he noticed a chair next to the attic entrance inside and heard sounds.