Well done. For future reference, if a driver threatens you verbally and you have a witness, such as your SO or even another driver who hears it, you can report the shouter to the police, as such threats are a crime in all states.

Saddest part is he had a child with him, and if you had been a psycho-cyclist and gone confrontational, the child might have be physically hurt to add to the emotional damage caused by such a father.