1 vet check. I know that they don’t think this is an emergency (might be too scared of your dog and don’t want to deal; maybe look for a different vet), but if a dog is hurting itself trying to get to other humans or dogs, this is very concerning behavior. Have them do a thorough physical examine + bloodwork to make sure there are no underlying causes for the aggression (he may start out as reactive, but progresses into aggression). Also ask about anti-anxiety meds

2 hire a vet behaviorist- they will be more qualified to answer behavior questions than your typical vet and are knowledgeable about medications too. The issues you described are quite serious and unusual, and will take lifelong management and training to effectively help your dog. The sooner you get help, the better.

3 have a serious family discussion about the quality of life for this dog. It sounds like his previous life was traumatic, and even with constant management and training he may never be okay. In some cases euthanasia for serious behavioral issues is the most ethical thing to do, but get SEVERAL professional opinions before coming to that decision.

I’m so sorry that this is a difficult situation. The best of luck to you