I failed to point out that he had 4 children the oldest died in childhood, the youngest born Feb 1870. Wife is widowed living with family in Arrow Rock in 1870 census. Thus best guess for Y.A. 's death is 1869/70.
Mary b 1859 d before 1870
George P b 1860 d 1958
Nettie Prudence b 1867 d 1951
Alexander Brooks b 1870 d 1941
As best as I can tell the 3 surviving children never married and had no offspring thus bringing this branch of the family to an end.
His wife, Mary Belle died 1 Oct 1875 and the children were raised by her sister Sarah Prudence Dickson who died age 91 in 1940 never married.