When Williamson and other officers tried to break up the confrontation, someone hit him in the back of the head.
Deputies say that someone was 24-year-old Joe Williams. He has been charged with assault.
Meanwhile, Williamson was airlifted to Duke University Hospital.
He is still unconscious, but family members are hopeful he will make a full recovery.
"Doctors have given us better news he's responding," Williamson's neice Tammy Evans said. "He can move his arms, he can move his legs, he sat up today so anytime you hear that, that's always positive news."
Janika Williams, 18, and Patrick Davis, 20, are also charged in connection with the fight.
Authorities still do not know what started the brawl or what Williamson was hit with.