I just don’t know that it meets the elements of the charges. If the State is alleging that the parent’s actions cause the deaths then they also have to prove that those actions were the proximate cause of the deaths and that no interceding events were the cause.
Or, the State can show that the parents failed or neglected to do something that caused the deaths. But the State must also show that the parents had a duty to protect the victims and I don’t think there was such a duty. I think a better case can be made against the school officials who were in the meeting and neglected to search the suspect and allowed him to go back to class. The school officials clearly had a duty to protect the students.

I’m afraid that the parent’s conduct (as it relates to involuntary manslaughter) might be awful but lawful.