Chisholm family history says he and his family moved north with other "Loyalists" sometime after Opothleyahola. They settled where Wichita KS is now located. Late in the war, his son moved back into the Indian Territory. I'm not aware of any official participation and I would not expect him to have any interaction with "Confederates" unless under duress. I have some information I got from a site that I think was called "A History of Chisholm" but couldn't find it with Google. I'll check my notes and send you what I can find.