Hello 13oO. Focusing on your main question, I can share my experience and perhaps it will help. My brain injury was 37 years ago. I had severe anger issues nearly that entire time, but had no idea it was related to the injury (physical health problems caused by the accident far eclipsed any psych problems).

I only figured out the anger was related to the injury after committing a misdemeanor threat to someone. The injury had damaged the precise area of the brain responsible for self-control over primitive emotions such as anger, violence, and worse.

The good news is that now that I know the cause (the injury, not me) I can control it, actually fairly easily. It took about two years to develop anger management techniques for myself, but the end result is that I can easily diffuse these sessions when they come up. I credit my martial arts training, and a renewed faith in my spiritualism (I am a Christian). How's that for a combo?

Best of luck with your situation.