There are records of patients at the National Archives of two Mobile Hospitals, Engineer Hospital, Jan. 13, 1864 to Apr. 25, 1865 and that of the Ross General Hospital, Sept. 1, 1863 to April 12, 1865.
What is the name of the man you search and does his time fit into the above dates?
Even with his name only, we might be able to narrow the search.