File a motion for speedy trial as guaranteed by the Sixth Amendment of the U.S. Constitution.
This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice. Laws vary widely from state to state. You should rely only on the advice given to you during a personal consultation by a local attorney who is thoroughly familiar with state laws and the area of practice in which your concern lies.
I do not practice in TN, but I may offer some general advice. As the first answer indicated, your cousin could file a written speedy demand request. Your cousin could also make a speedy demand orally next time he is in court.
Good luck to the both of you!