No, that isn't "discipline"

Yes, a child who gets sent home from school for behavioral issues needs consequences.

No, beating that almost 8-year-old child so hard and so long that she vomits, then making her clean up the vomit, and leaving your handprints on her backside that are still visible two days later, is not proper discipline. It is abuse.

This happened when she went to her father's house for the weekend, three days after the school called him because she needed to be sent home and they couldn't get hold of our daughter, who isn't allowed to receive phone calls at work.

Her brother corroborated this incident. He didn't see it, but heard it.

Get help, dude. You need it. Perhaps the legal system will help you to realize that.

I slept on the downstairs sofa last night. I wasn't willing to be asleep safely in my bed in the unlikely event that he finished going off the deep end and invaded my home, where the other two siblings were sleeping so that they wouldn't be a distraction to - or distracted by - the visit from the police.