Roman Mendez, 6, and Elias Wolford, 5, were in critical but stable condition following the attack on the Feather River School of Seventh-Day Adventists in Palermo by gunman Glenn Litton.
A shooting at Apalachee High School in Georgia left four dead and nine injured. The area was secured after an hour.
"After 10 days, he lost his battle and this tragedy took his life,"
The sheriff did said that the shooter was identified as a 17-year-old student at Perry High School.
A 14-year-old girl in Russia shot and killed a fellow student and wounded several others before killing herself.
The case appears to be the first time that parents of a teenage school shooter have been charged for involvement in their offspring's alleged crimes.