The records are very spotty. What is the name of your grandfather? Here are the two Haynes listed in the roster.

James D. Haynes, Private, Company G, 21st Alabama Infantry, admitted Post Hospital, Fort Morgan, Ala. January 23, 1864, Pneumonia, sent to General Hospital January 29, captured August 8, 1864 at Fort Gaines, received at Ship Island, Miss. from New Orleans, La., October 25, 1864, exchanged at Ship Island January 4, 1865, captured in hospital at Mobile, Ala. April 12, and paroled there May 11, 1865, resident of Mobile, Ala.

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Thomas C. Haynes, Private, Company G, 21st Regiment Alabama Infantry, admitted Ross Hospital, Mobile, Ala., January 28, 1864, Typhoid Fever, Ensipelas, Remt. Fever, died February 24, 1864

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The men I found who were captured August 23, 1864 at Fort Morgan, were shipped from New Orleans, La. September 27 to Elmira, N. Y. arriving October 8, 1864

Note, how they were handled before arriving at New Orleans is not revealed.

M311: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Alabama