Clowns... they were friends and both trained by Futch. Frazier did knockout Norton the first time they sparred, but after that Norton was on even terms with Frazier according to stories
I don't emember but Norton talked about it in his book. Norton wanted to go, and Frazier claimed that he did not want to fight his friend.
American Football is not Boxing. The Williams sisters play tennis against each other and many other siblings compete in other sports but Boxing IS different.