This is all I could find on Major Garrett:

George Washington Brooks Garrett, age 21, 2nd Lieutenant, Capt. Philip Holcomb’s Company (Tippah Tigers), 2nd Regiment, 1st Brigade, Mississippi Vols.* enlisted August 24, 1861 at Ruckersville, Miss. by P. Holcomb for 12 months, promoted Captain November 19, 1861, promoted Major April 24, 1862, captured at Nashville, Tenn. December 16, 1864, subscribed to the Oath of Allegiance to the United States at Johnson’s Island, Ohio, July 25, 1865, age 24, resident of Jonesboro, Miss., light complexion, light hair, blue eyes, 5’ 8”

* This company subsequently became Company C, 23rd Regiment Mississippi Infantry

M269: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Mississippi