Was my friend wrongly punished for this?

Today at lunch, these kids that were two tables away from my table were calling my friend a "Paki". My friend got up and yelled "Why don't you come over here and say that?!". So one kid got up and called my friend a Paki up to his face and pushed him. Then all of a sudden, the kid who pushed my friend started swinging at my friend and got a few punches on him. After about 3 or 4 punches, my friend (he does martial arts) did this self defense move and "subdued" the other kid. As a result of the move, the other kid who punched my friend was on the floor and security guards came and took both my friend and the kid who punched him. They both got ISS and OSS. My friend DID NOT strike the other kid in the process of his self defense move. It simply got him onto the floor so he could no long be a threat to my friend. Was my friend wrongly punished? I really need to know, because he is furious about this and his parents are too.