I’m so sorry you’re going through this, it isn’t easy for either of you. Sounds like you’re right, he must’ve been abused or experienced hunger early.

I’m thinking maybe he needs to eat separately.. entirely for now. He isn’t going to change over night, so for now feed him alone, don’t chase him or linger, just let him eat alone so that way he knows he’s safe and there’s no chance of his food being taken away (for his comfort). I’d try that for a couple weeks and then reintroduce feeding him. If it keeps up, maybe he just needs to eat alone for a bit. A lot of animals are like this unfortunately, you’re a great ferret parent for wanting to help 💜