Is your husband concerned that he can't find a job someplace else because there's no one he can use as a reference?
It that's the case, maybe he needs to volunteer, take a class, do anything to hustle for references. Your father is not going to cut it, even if he DOES offer him a job back. You'll never know what kind of reference he could leave for your husband. Your husband can't take that chance.
The same goes for you. Build a list of professional references outside your father's realm BEFORE you start hustling for a job. Professors, volunteer coordinators, you name it. You don't have to ask them straight away for a reference - just touch base every once in a while and if you can, ask them for advice. Most people are SUPER flattered that you would consider them in a mentor role, and more than happy to oblige.
I can also say this speaking from experience - you may find that once you are financially independent of your father that your relationship changes significantly for the better. Not because you'll get his approval. Not that at all. But he'll realize that he absolutely has no power over you. He can scream about cutting you from the will or out of a job and it will be just inconsequential hot air. And you can walk away from it.