Phan Huu Phuc, deputy director of the National Children’s Hospital which admitted the boy from Phu Tho General Hospital the previous day, said the boy was in a deep coma, had kidney failure, required ventilation and blood filtration.
Phuc said his hospital consulted doctors from Hanoi's leading facilities Bach Mai and Viet Duc on treating him.
"But his conditions just developed worse and he died this afternoon," Phuc said.
On March 17 the eighth grader at Viet Hung Middle School was playing at a communal yard when he quarreled with a 12-year-old boy.
The latter went home to fetch his older brother, Truong Van Minh, who punched the boy in the face.
The boy was taken to Duc Giang Hospital before being transferred to Military Hospital 108.
He was diagnosed with traumatic brain injury and placed on oxygen support.
His family later moved him to the Phu Tho General Hospital.
The Long Bien District police on March 27 arrested Minh, a 10th grader for "intentionally harming a person."