There are so many outstanding issues:

"and tried to register the Corp but received a letter basically saying that is not allowed."

For FL only?

"I have asked them to check and see if an S-Corp would be allowed"

Why is there even a Corporation? This requires payroll. Is there ongoing business that makes payroll reasonable?

"Get a copy of the commission agreement / broker contract and see who signed them."

Because legally, this is the business arrangement.

Your Taxpayer is responsible to understand contracts. Is the signature for the name of "Joe Doe, President of JD Corp" or "Joe Doe" as the individual?

For a FL S Corp Agent, the license gets transferred:

"Using your entity

One of the biggest mistakes many agents make is forming a PA or PL, but never changing their license with Florida Real Estate Commission (FREC). The problem is that commission checks will continue to come to your individual name and you wont reap the benefits of your business entity.

Here is how to properly use your entity:

1. Obtain TAX ID Number
2. File an election for the LLC to be taxed as an S-Corp (more information below).
3. Change your name with FREC to the name of the LLC.
4. Change your name with your broker to the name of the LLC to ensure checks are paid to the LLC and not your individual name.
5. Open a bank account for the LLC and obtain credit or debit card.

Ultimately, you will be acting as a business rather than an employee. Why? If you don't act like a business, the IRS, nor any court, will treat you like a business."

So, what is the status of their license?

If your taxpayer could identify to resolve all the legal issues, and establish the specific parties in the relationship, that would be helpful.