Half his audience (totaling 4 people) will never see or hear about his tweet so they will still believe it to be true.
The FCC provides a method for registering complaints about a broadcaster’s failure to comply with standards of fairness in their broadcasts. This FCC complaint also provides a means for requesting the denial of a broadcaster’s request for the renewal of their FCC broadcasting license. A broadcaster cannot disseminate false propaganda if and when they no longer have an FCC license to broadcast the propaganda programming.