If he had committed fraud, then there is a very simple defence of it being true which the WBTS could use to rebut the slander allegation at least. But they don't seem to have done that.
Obviously, we cannot know the rights and wrongs of what happened with his business dealings. But can you imagine a business relationship going bad like this leading to similar sanctions outside of the JW bubble? Or having men, totally unqualified to listen to the information put in front of them, deciding on whether or not you'd committed fraud and whether or not you could have a normal family life?