What should this person have done??

Question

One of my friends was in the mall at L.A
He was with his little brother and his little brother said a bad word out loud.
My friend was laughing. Well my friend little brother came in front of another person on accident and that person pushed his little brother out of the way. His little brother was then beaten because this person was crazy. The person punched my friend's brother in the face and threw him against an arcade machine, tried to break his brother's leg but before he could. My friend stabbed the person with a knife and kept kicking the lowlife. I told my friend to stop and i said lets put the low life against the arcade machine and keep kicking the lowlife. My friend's little brother was bleeding and hurt and as for the low life was sent to the hospital then sent to jail. The low life had a concussion and was "brutally" beaten. My friend cannot parcipitate in school sports or extra cirricular activities.
Why did my friend get punished because he was standing up forsomeone

Answer 1

Self defensive should only be that. Once the guy was off the kid, the focus should've been getting the little boy help and letting the authorities take care of the man. I'm not sure why he's not able to participate in sports and other activities, that's a question better suited for the school authorities and parents. Maybe they felt given the brutality the man suffered, he went to far.

Answer 2

Self defense and the defense of another person can only be considered so. Once you cross that line, you are assaulting. You should've called the police once that person was down and he would not have been in that situation.

Answer 3

Because he used a weapon against someone that didnt have a weapon.

Answer 4

Ask his parents.