In every state in this country there are statutes prohibiting unfair debt collection practices. Likewise there is a federal law prohibiting such practices as well by third party debt collection companies.Each state has its own definition as to what consitutes an unfair debt collection practice separate and apart from the federal definitions of such.From what you have written, the leaving of false and deceptive messages by the third party debt collection company could very well be an unfair debt collection practice that could be reported by your brother to the attorney general of the state he lives in.Threatening a lawsuit for collection purposes is one of the many prohibited acts under many state's unfair debt collection practices act.If the calls persist, your brother and his wife may want to consult with an attorney experienced with debt collection practices.Good luck.