Maybe.
I don't know enough about that law to comment. Questions I have...and yes, I can and probably will Bing! it and learn something about it...does the law protect whistleblowers who remove (take....steal) government documents, if those documents are critical to proving what that person is blowing about? If it's possible for some bureaucrat to destroy evidence and thus deny the blower his/her evidence, then does the law excuse the removal of said evidence?
My only....very limited....exposure to the whistleblower circumstance occurred in a state agency. That case is still in litigation...now about 4 years later...the state itself is on the hook, and those on the other side are openly complaining they are being denied justice. That the state is dragging its feet hoping all this "just goes away."
In the case of this Dennis Cain, I suppose we'll learn more later.