I did something similar when I was about 13.

Best friend at the time had a bone marrow disorder where he couldn't make new blood so he pretty much lived off of transfusions (he later died due to a failed marrow transplant). There was one kid who was a neighborhood bully and he used to give Joe a ton of shit (because he knew that Joe couldn't risk fighting or he could die from bleeding).

One particular time, the bully and his "little" brother showed up at the local video store where we played Mortal Kombat, and started trashing Joe's bike. Some kid came in and told us what was happening and I ran outside completely livid.

I start yelling at the bully and tell him to fight me right there. He claims that it wouldn't be a fair fight and that I should fight his brother behind the local school.

We all ride over to the school and here I am confronted by the bully's brother who is my age. He didn't seem too into the whole thing but he didn't want to be a pussy in front of his brother.

Well, at this point I had boxed for a couple of years and my uncle had trained me a couple of times a week for over 6 months at this point. I was enraged and probably looking for an excuse to test myself.

The fight was quick and pretty brutal looking back on it. I missed a few times before finally connecting with a straight right that shattered his nose and required reconstructive surgery. I also ended up hitting the bully in the face with a rock that I threw as they fled... I think he ended up needed 6 or 7 stitches from where the rock hit his forehead.

Joe died less than a year later. At least he died knowing that I was there for him.