Found this
Nov. 14, 1889 Mair applied for a pension while living in Kansas (application #737801/certificate #596902
July 6, 1891 his widow Mary T. Mair applied for a pension while living in Kansas (application #519197/certificate #360565)
The 1890 US Census was destroyed by a fire as was parts of 1890 US Veterans Census

Mary is listed as a housekeeper at Whiting, Jackson County, Kansas. She was born in March 1840 in Indiana and has one living child.