Shawn, The following is his listing in our "Lest We Forget" 7th Mississippi Roster on the main roster as well as the Casualty Roster from Shiloh. Unfortunately we do not have any post military records on him. Please contact us so we can include you if we find any additional information on your relative. Definitely visit the 7th Mississipp website as my fellow 7th Miss. researcher, George Purvis, suggested.
Re: John Rials - MS 7th Infantry

From the “Lest We Forget” Roster:
"Company E 7th Regt. Miss. Inf.

Casualties at Shiloh
Rialls, John Aaron Pvt. (Rials) Shot in head; left arm and left hand; discharged; 7-23-62Born Copiah, Co. (Hadskey). (See also Rials) “wounded in the arm and hand at Shiloh at 8 A.M. April 6 on the right wing.” “He received a disability discharge on July 23, 1862, Dr. Buie's report indicates a loss of use in his left hand” Mitch Sanders 10-2008.

Main Roster:
Rialls, John (A. “Aaron”) Pvt. (Rials) WIA Shiloh. Shot in head; left arm and left hand; discharged; 7-23-62. Born Copiah, Co. (See also Rials) [There's no mention of a head wound in his records as suggested by Hadskey, he was “wounded in the arm and hand at Shiloh at 8 A.M. April 6 on the right wing.” He received a disability discharge on July 23, 1862. Dr. Buie's report indicates a loss of use in his left hand. Apparently this was the end of his military service, I did not find him in any other units.-Mitch Sanders email 10-14-2008]"

Ron Skellie
"Lest We Forget-The Immortal Seventh Mississippi"