Based on your description of events it sounds like the husband was the one bringing the get into a business dispute.
Why should his dispute with his father in law about who owns the business have anything to do with him giving a get?
There was barely a few months from when they were separated before the GET REFUSER campaign started. FIL knew that it would come into dispute so immediately put him on defense by demanding the get asap so he wouldn't have to give the rightful share to his SIL. It was well documented that the FIL lived in canada for many years and only moved to boca to start the business WITH S. Being that he married the guys daughter, I doubt they had any legal paperwork showing an actual partnership.
in addition, they refused him rights to his kids etc. It got ugly really quick instead of coming to a reasonable settlement. Its the liberal view of halacha that says get first, talk later.