Billy witnessed a hit-and-run but is gravely ill with cancer. xavier, who was injured in the accident, would like to preserve billy's testimony for trial in case billy dies before the trial date. what should xavier do?

In the stated case Xavier can take Billy' deposition which can later be used as testimony in the court.

Deposition means an out-of-court oral declaration of a witness in the Law of the United States that is reduced to composing for later use in court or for discovery purposes. It is usually utilized as a part of prosecution in the Unified States and Canada.