Ugh...torn.

[nschildcare]

If dcb was doing it to another dck would you allow him to stay there?

I wouldn't stand for that behaviour towards anyone, let alone my own child. The fact that you have communicated with parents and they are on board with helping curb it, yet the behaviour is still continuing, even escalating, is worrisome.

I would term immediately. Parents may even be able to find something else for dcb and leave the baby with you.

Either way, daycare needs to be a safe place for everyone, your son included.