You can sue an executor who violates either the plain terms of the will or his fiduciary duty (law-imposed duty to be honest, to be loyal to the beneficiaries' interests, and to not profit at their expense except as specifically authorized by the will or law). This kind of legal action is commonly called an action "for an accounting" since you ask the court to make the executor "account for" his conduct. The court can order him to do or not do certain things, to repay anything he improperly took or diverted from the estate, or can replace him as executor. Contact the clerk's office in the probate court; they should be able to direct you to instructions or forms for doing this.