Brokendad, Welcome to the Forum, I am so sorry you are in this position with your son. Agree with the advise given, I would not contact him however, , he must sort himself out, however hard that is, otherwise it’s just keeping this cycle going. He needs to see you because he loves and respects you, otherwise there's no point.
Use this time to heal yourself, you have taken on your shoulders the responsibility for how he has turned out, you blame yourself for what you haven’t done without recognising your qualities. You deserve a life, to feel valued and enjoy yourself once more. Please whatever else you do or don’t do, heal yourself, start liking yourself again, stop the blame for things out of your control.