There are levels you forgive someone as people aren't pets where if they chew up the rug you tell them off then forgive them after.

No need for eye for an eye, if they essentially betray you like this, cut them off completely. No help with funds, no assistance, no contact. I know the argument "but he's my son, I raised him how can I abandon my child" but do want to fund his decent into depravity where he'd gladly and gleefully backstab his own or at least make a stand and show he lost a safety net.