Wow. This new info that was just released is mind-blowing to me. She had warned him via text not to do that anymore, including THAT day after she left for work?
This is absolutely the father's fault, however the mother clearly knew this was an on-going issue and that he was still doing it, despite her warnings. And yet, she continued to let him be the sole carer for the children.
Kind of makes one wonder why daycare, a professional nanny, or even a teenager off of school for summer break wasn't hired to either help out at home or be solely responsible for the children's care. They don't seem to be struggling financially, even with being a one income household. And he also has a degree (in biochemistry) He clearly wasn't enjoying being soley responsible for the children's care.