I'm pretty sure Kentucky is an at-will state, meaning they could fire him at any time for any reason, as long as it's not discriminatory. They don't really technically have to prove he stole, nor does the tape have to exist. If they suspect him of stealing, or even if they don't, they can terminate him unless he had an employment agreement that designates otherwise.
But in the event he wants to pursue it, Find Law, My Employment lawyer, Lawyers.com and Legal Zoom all have resources and employment attorney references he could look at.
No, I'm not an attorney. And I know you won't take my advice on the matter even if I were. But having been involved with several employment law situations, I would say he's probably going to find there's not much of a case, at least based on the limited info you've supplied here.
EDIT: here is a place in the Cincinnati area that explains wrongful termination, but also advertises an offering for a free consult.