rugwithlegs

I hear a few things here.

You are a victim of violence with strong negative reactions to any perceived threat of violence. Your instincts may be right. Your history is part of who you are; same for all of us.

I was unclear if you had to stop training completely for a year? While he kept training?

He is a veteran, and as part of that there are horrible statistics on PTSD, suicide, difficulty coming home. Not just personal, but also anyone he served with - friends will have likely melted down, been admitted to psychiatric wards, killed themselves, or it could be a birthday of someone he watched get blown up, or he might have had a flashback nightmare to his most frightening close quarters combat. No questions, no way to know. Your own safety comes first of course but the one guideline from O Sensei's religion is to reconcile dicotomies.

Brown belts also need to break away from safe, predictable kata practice and now get into multiple target randori - most schools I have seen just throw people in, and few schools address the psychology of the exercise explicitly in my experience. Things that can be sitting on the back burner or repressed most days have a way of getting pulled out. I am not sure how to run the classes best myself. I never served, but as a nurse I would come to practice after watching a patient die. It affected my practice. PTSD is a huge issue for the USA now, and I'm guessing many a dojo is dealing with someone affected now.

Vets can have baggage. They can also have experience and insight that no amount of safe dojo training can ever bring. It helps my Aikido to pick their brains. One guy in our dojo was asking questions about martial effectiveness which caused several senior students (who never served) to roll their eyes and judge him harshly. Turns out he was in the army and had been deployed for years, so his questions were partly memories. After cutting him some slack it turns out he's a very gifted visual artist in multiple media. He can't explore a martial side of himself at home with his wife and two young kids, so he became part of a dojo.

I would go to the instructor, if you are no longer comfortable talking with your former friend. Talking behind someone's back with a dozen members of the school wIll probably end badly. Stay safe, but try to do this with some empathy and with a goal of having this resolve well for everyone. It's kinda what we are about.