Negro Rivera was stabbed in the neck Wednesday morning outside PS 12 in Westchester Park.
Police recovered a pair of bloody scissors at the scene.
A 15-year-old now faces charges including attempted murder, and 16-year-old is charged with assault and weapon possession.
Rivera remains hospitalized in critical condition.
Mom Cassandra Rivera could barely contain her grief as she stood outside Jacobi Hospital late Wednesday afternoon.
Eyewitnesses say Rivera was confronted by some teens from another school when it quickly escalated into violence. The attack witnessed by horrified students as they came to school this morning.
"His whole like neck was bleeding," one student said. "He was in shock like nothing happened."
Rivera's mother says her son was in the custody of juvenile services and was in the process of being placed in a foster home. She was surprised to hear he even went to his school.