Thanks Alan. I have Art's book, and I assumed there was little or no fighting at Macon, Ga., in latter April 1865 where he was "captured". As it was two weeks after Appomatox, I assume the Macon Command had by then word of Lee's surrender and the Judge Advocate was not prepared to continue to wage war. He was (at least) at Chicamagua, TN, with the 20th La., so he must have seen some combat.
I believe my ancestor was at Macon, along with another Lt. LeBlanc from another unit sent at the same time, for temporary duty with the Judge Advocate. And I further guess at least part of their duty there was to translate writing and speech for French speaking soldiers who were involved in Court Martials. But that's all guess work.