An adult in a position of power (a teacher) abused a child (most likely many children) in his care.
If the victim gets money, we call that restitution.
No it is not restitution in this case. You sue in a court for restitution. You threaten to expose when you blackmail.
What he did, if true, is terrible. That does not excuse the demand for ongoing hush money well over a million dollars. That’s not justice or restitution. It is closer to prostitution.