Discrimination in our school

Only a year ago, we had an USA partner in our class. This person was my friend in good and bad times. He went to our School at 5th grade. His problem? He was fatter from the rest of us. He was product of discrimination from 5th grade to 1th medio, year that he went back to the United States, were he got his friends. A particular case were some class partners who constantly were discriminating him only for his physical appearance. I still talk with him sometimes by the internet, he's happy in his country now.