Ann,The Cartel was in force when your kin was a prisoner.It had its complications from the start but, spiraled apart after the fall of Vicksburg in July of 1863.Shiloh was April 1862.I need to go through official records but in general. He would of been loaded on a train possibly the IL.Central south or the train to Quincy west then onto River Packets to Vicksburg.The first step was Parole him stating he would not help the war effort in any way till he was rightfully exchanged.The south as well as the north had parole camps (Camp Douglas was one in the north)Possibly Camp Moore in LA.?till he would of been exchanged man for man rank for rank.He most likely was exchanged at Vicksburg.In my 6LA Inf. case,though in the Eastern Campaigns,he returned to LA. (twice)and was resupplied(uniform) From there he would rejoin his Regiment if not disabled from his wound.Do you have his entire CMSR?