Yes, William H. Terrill was the father of the two Generals by that name - James B. (CSA) and William R. (USA). According to my source, William H. Terrill served on Elzey's staff in June 1862 during the march from the Valley of Virginia to Richmond. He was with Elzey at Anderson's Turnout, near Hanover Junction. The source does not state what position he held. It was most likely as volunteer aide. Thanks to all who have responded.

Richard L. Armstrong