I'm afraid I've misspoken. Lt.Duke's bro was Sgt.Maj.John W.Duke of Sypert's 13th KY Cav. And rather than keeping the LT in Louisville, he sent him on to Johnson's Island, where he was not released until 14 JUNE 1865. As for his brother, Sgt.Maj.Duke, he was either executed as ordered by Gen.Stephen Bast--- Burbridge, or was kept in Lousiville Prison. More as soon as I find it.
-Mike
PS: Many KY Confederates were also among the "Immortal 600"- POWs intentionally exposed to artillery fire. Get back to me and I'll have more for you shortly.