Lawyers have a power as officers of the court to issue subpoenas, pursuant to which courts require witnesses to give testimony. Anyone whom the lawyer believes to have relevant, admissible evidence and who is within the court's jurisdiction can be subpoenaed, and they have to show up and give truthful testimony. Witnesses don't get to pick and choose about whether or not they'll testify. Once they've been subpoenaed, they have to show up and say what they know, unless the information is privileged. If there's something unduly burdensome about the subpoena, or if the court doesn't have jurisdiction over the person because they live too far away, the subpoena can be "quashed." But disobeying it isn't an option. The court can sanction the witness for failing to obey the subpoena by imposing fines. The court can even send out a law enforcement officer to go pick up the person and bring him or her to court.
That's the general principle. Inherent in the idea of subpoenas is that the witness HAS to give testimony, has no choice. There are limited circumstances where a subpoena can be quashed, but outside of those, the witness takes the stand and the witness answers the questions.
Not legal advice as I don't hold Florida licensure. I'm just talking about the general legal principle based on the facts you describe. If you need legal advice, please consult a lawyer who holds Florida licensure.