Gordon, the Independence County Library has some good Genelogical resources and has back issues of the Historical Quarterlies. these quarterlies contain histories regarding the units raised in Independence County and life in the county during the war.
I am not sure what prison records and medical records might be included in his service records, but I would certainly order his records, (making sure you request the complete file), you can order them via the top of this website page. The Arkansas History Commission should have information regarding the military prison at Little Rock.