Unfortunately, imo, the transgressions of the Mom were allowed to be put under a microscope in court, although she had nothing to do with the head biter father's abuse that eventually took her son's life.
Yet, the drug and alcohol transgressions of the killer were covered up in court, due, imo, to that travesty where his parents were allowed to 'try out' testimony (white wash) re their son's aberrant behavior in court, before settling on the most flattering accounts presented by vip father.
For Pete's sake eventhe killer's last minute call telling his mother to change her testimony wasn't allowed in court.