After further research, I have found I need to remedy a few previous statements:
1. The Abel Carnes buried in Leavenworth, Kansas is the Abel and Mary Ann Curnes. I was able to find records from the National Homes for Disabled Volunteer Soldiers 1866-1938 which note the DOD of this abel as May 20, 1920 in Leavenworth, Kansas and that he was a member of the 73 Illinois Infantry. It also lists his nearest relative as his son-in-law, John Berryman. John Berryman is the husband of Abel and Mary Ann's daughter Leona/Lenora.
2. I have come across records that indicate Abel Carnes, father of Nancy and Mathias Carnes, is buried in Coles County, Illinois. This Abel died about 1882. This Abel was with the 78 Ohio Infantry, I believe.
I had to map out both Abels to get everything straight, so the following links are for each of them.