I have found that there are wild discrepancies in the positng of names in the hosptial records and on the grave markers. Part of the problem is simply one of transcription; the records are faded, blurred, and exceptionally hard to decipher, in many instances. The 19th Century penmen and penwomen (is that a proper term?) wrote the letter "J" so that it looks like the letter "I', and vice versa. If your ancestor was gravely wounded, he may have bene able only to mumble a name; the soldiers were not carrying any form of identification, at least as we know it. Units got transposed. So in fairness the identificaiton of names and units listed on the tombstones are a hit or miss thing, or at least that's my take on it. I personally inventoried Rose Hill Confederate -- a beautiful spot, incidentally, with a huge Confederate National flag, lit at night, flying over it. You can see the Confederate cemetery from the Atlanta-Savannah Interstate as you pass through Macon. It is exceptionally well-kept, as indeed are most Confederate cemeteries in Georgia. To go back a ways, the UDC also had a published cemetery listing for Rose Hill Confederate, and it varies from what I found on the ground. I have no idea where that published UDC listing is now, maybe somebody can put you on to it. I am sure that Georgia Department of Archives and History has one. Perhaps a phone call to them might get you some additonal info.
Is there any chance that he died in one of the hospitals short of Macon. The casualties were dropped off wherever they could find room. There aree Cofnedrate cemeteries in Forsyth, Griffin, Milner,and several other little towns between Atlanta and Macon. Others were sent to hospitals in LaGrange, Newnan, Covington, Madison, and other points. I'm not aware of any hosptial records except what may be found under the individual's ane in the Compiled Service Records.
However, there is a Civil War Medical Museum at Chimborazo Park in Richmond, Va., which apparently serves as a "clearing house" for all medical matters for the War. I do not know their phone or E-Mail, but tyr to Google the National Park Service, Richmodn Military Park, or something like that, fi you want to try them. They may know of the locaiton of hosptial records in some National Archives Record Group, or elsewhere.
Hope some of this helps!