Cosny was a soldier and later, a farmer.
He may have met JW at the USMA, West Point, NY, from which he graduated on 1 July 1852. He resigned in 1861 and served with the CSA army, rising to be a Brigade Commander. After the war he went to California as a farmer.
Cullum Memorial Edition, Register of Graduates and former cadets, United States Military Academy, West Point, 1980, no. 1552.