I don't know how integrated your son's school is and how much he is made to feel like an outsider because he is Native American. The principal's suggestion to cut off your son's braid reveals an astonishing lack of sensitivity and leadership on his part. Perhaps there are Native American advocacy groups that could meet with this school's administration to discuss the need for diversity education within the school system, for both students and teachers. All schools are required by federal law to provide a safe, harassment-free learning environment for all students. It would appear that your son's school is not providing him with what he is entitled to by federal law.
Beyond the school harassment laws that need to be enforced and the diversity training and education that should be incorporated in the schools, we still face the prejudices of the children who are hurtful to your son. Unfortunately, children, as well as adults, will often mock those who are different from themselves. Prejudice in kids is borne out of ignorance and fear. Kids need to be taught how to hate, but they can tease merely by being swept up in what their peers are doing.
Please try to get help and support from any of this school's teachers, other minority group parents, members of the school board, and Native American political and educational organizations. Someone in a position of political power and persuasion should be moved by the thought of a little boy attempting to take his own life because of being teased about his braid.