Technically, I understand what you are saying. However, the term prisoner to most folks implies that the person is in the custody of someone else who controls and/or restricts their movements. I was simply trying to make sure that Mr. Taylor did not come to the conclusion that his ancestor was incarcerated. Since Taylor was likely not in the custody of a Federal officer except perhaps for the short time he was standing in line to receive his parole, I think the use of the term "prisoner of war" could be misleading to the casual reader.

From Merriam-Webster: prisoner - a person deprived of liberty and kept under involuntary restraint, confinement, or custody ; especially : one on trial or in prison