Sheila,
I asked about the Krebs name because I was once researching a mixed French & Cherokee/Choctaw family from Winston County, MS with the last name Krebs. The progenitor was an Etienne Krebs who had married a lady who was half Cherokee and half Choctaw. There were four sons who were all Confederate soldiers. Three did not survive the war. I am a mixed-blood Cherokee, so this story was very interesting to me.
I have looked at John T. McGlann's CMSR and a bounty record. The last entry is for August 31, 1864 and he is in a General Hospital in Greenville, AL. I can't tell if he is a patient or is assigned there on detached duty.
I'm sure you know the 57th Alabama Regiment was sent East after the battle of Franklin and Nashville, so as a unit they could not have participated in the battle of Blakely; however, it is certainly possible that he may have been separated from his unit and ended up in Mobile. Unless you can find a document from that period or a post-war reference to his death, I don't know if the exact location of his death is knowable. Perhaps, Alan or others might be able to pull something out of their hats.
Good luck!
Jim Martin