Yes, it's more than possible; it's par for the course. In a criminal case, it isn't the victim that decides whether or not to continue the prosecution, it's the government (in this case the state). Your uncle should let the prosecutor know that he wants the charges dropped. He should call the prosecutor's office and request a waiver of prosecution. I am not saying this will cause the state to drop the case, but it can't hurt. Good luck. Please note this email does not create an attorney client privlege.
Under our Anglo-American system of law, the government prosecutor, not the "victim", is responsible for bringing the charges before a court of law. Although the basis of the government's complaint is information supplied by the victim of the crime, it is the responsibility of the prosecutor to bring the charges and to terminate the case when appropriate.
As a general rule, the affidavit used to secure an arrest warrant for criminal prosecution is made under oath and upon penalty of perjury. The court has the inherent power to punish the person bringing the complaint if it is later determined the affidavit was made falsely, in bad faith, or without justification. If the court should find that your uncle pressed charges in effort to "scare" the other person, or did not have a reasonable basis for the complaint, the court may hold the uncle in contempt, or may bar further warrant applications.