Our trainer would 100% say that the trauma of seeing you knocked on your ass is making him feel like he has to protect you.
Disagree with “dominance” like some harsh insistence on it, but he needs to relax, and it’s impossible for him to do that if he feels he must protect you. He has to know you can protect him, and take care of him.
Can you get professional help? It really helped us. Getting the whole family on the same page and using the same training strategies will help so much. And don’t worry, behavior can be modified.