How to cope when emotions are on overload

Hi dear Nicholeen. I have a question about giving myself a no answer when my emotions are on overload. I've heard you say that we need to stop thinking about it and drop the subject, but I'm really struggling with doing that. Last night put me over the edge because my adult son and my husband went at it with words, to the point that my husband called the police. I already have serious traumas with confrontations in my life, and this was beyond terrifying for me. I tried desperately to bring peace and reasoning to the situation, but it was like I wasn't even there. My husband was trying to remain calm, but my son would not stop talking. My son has made incredible strides of improvement, but he refuses to accept his role as a brother and not father to my daughter. And this is what finally got to my husband and he exploded and they were verbally attacking each other. My son tried, in his own way, to be calm but he too lost it. Could you please give me some hands on tools that I could use to stop thinking about this awful experience, besides breathing? Thank you.