His records show he died August 11, 1863
Where and from what cause? G. H. Mobile [No indication of cause of death]
Number of certificate 42
Confed. Arch., Chap. 10, File No. 4, page 190
I take it that he died August 11,1863 at the Ross General Hospital* in Mobile, Alabama along the route his regiment was returning home after being paroled at Vicksburg. Mobile being along the way troops were traveling East. I believe there may be lists of Confederate burials in Mobile. You might want to post this query on the Alabama message board.
* Unfortunately, the only register of patients in the hospital records at the National Archives datets from Sept. 1, 1863
Major Raleigh Camp, 40th Georgia, wrote from Enterprise, Miss. on July 20, 1863: "We are now to be furloughed for 30 days, and we will leave in a day or two for Georgia via Mobile." They had marched on foot from Vicksburg to Enterprise. From here they took the trains to Mobile.
As to Certificate no. 42, I doubt very much this actual document could be located, this was where the clerks in the War Dept., ca 1900, sourced the information which they found in the Confed. Archives recorded above. If cause of death had been indicated, I'm sure the clerks would have so recorded in his records. In any case, what documents are available will be found in the bowels of the National Archives building on Constitution Ave. in Washington, DC.
You might be able to learn more of their route home from this book:
Herring, Dorothy H. Company A, of the Fortieth Georgia Regiment in Confederate Service.
Jonesboro, GA: By the Author, l988.
See also: http://www.nwinfo.net/%7Ejagriffin/40th.htm
& http://www.google.com/search?client=safari&rls=en&q=40th+Georgia+Infantry&ie=UTF-8&oe=UTF-8
Also, you might contact Kay Borden who is listed as an "Expert" on the regiment:
40th Georgia Infantry kborden@mindspring.com (Kay Borden)
http://www.generalbartonandstovall.com/