There is a whole set of NARA film available on just Confederate military medical personel. Most of his service record will be found there. It should tell you what unit he was assigned to, as well. You will probably find additional records in the compiled records of that regiment (assuming he was assigned at the regimental level). There is a third set of NARA film that *may* have additional records. This set is called "Unfiled Confederate Slips". I found many records in that film of my cousin who was a Confederate medical officer.