G.H.
A judge will see right thru this type of scam. It's great that his customers are still writing checks even if they are made out to cash. As long as they are writing checks there is documentation to prove that they were past clients writing checks to the business & suddenly since the divorce proceedings the clients are making the checks out to cash. The clients can be subpoena too. Depending on what kind of business it is maybe there are some type of receipt log or something to show services were performed or distributed. Also depending how long the divorce has been going on if his business income took a nose dive like you say then it won't be hard to figure it out!