Although the state will have a harder time without a victim, you need to give more facts to a Florida criminal defense attorney for a better answer. For example, did you admit to anything? Was this credit card fraud or was it cash? Are there any other witnesses?
Is it possible that the state just decides to drop this case? Yes. However, they could still pursue it if they wanted to. Restitution could, arguably, go to the victim's estate. One would think this would be a nuisance that the state may not want to deal with.
If the victim has died, this very well could impact the State's ability to prosecute the charge. In any theft case, there is no criminal intent if the victim has permitted the taking or "borrowing" of the property. Absent other witnesses, or an admission from the Defendant, a theft charge can be difficult to prove without a victim.
However -- be aware that in certain circumstances, the charge may be proveable without a victim.
If the charged is proved, restitution could still be ordered by the Court. Where it gets paid would depend on the facts of the case; whether or not there is a spouse or offspring, etc.