Oh, well...you know the answer.I'm not going to provide details because there were witnesses.
It involved my wife and one of the grandkids.
It came to a head after a month and 4-5 instances of the same behavior.
Our Daughter-in-Law reacted.
Our Son was not present that day.
I was there.
This is probably THE most common (besides politics) reason for the cut off.
There is nothing you can do now. Your daughter in law is going to be forever pissed. Your son can't do anything without making his life even more miserable than it already is...