I would like to know the age group. Way too much testosterone floating around in a girls game as well as parents living through their kids. If one of them were the head coach he needs a massive overhaul of his people skills. As hard as I know it can be, you have to keep control of your head. The dad seemed to be the instigator but the head coach should be able to try and diffuse and just walk away.
I'm not someone who would back down from anyone but.....as a coach I have been given a great responsibility. Set an example for my girls and my organization. Try to teach the game as well as hopefully have a positive impact on the growth of the young ladies on my team. Just walk away.