Adda (Todd) Cottom and Nathan Cottom

John H. Cottom, b. abt. 1852, Indiana, d. aft. Jan. 31, 1889 and bef. July 2, 1898 married May 10, 1877 Adda M. Todd b. abt. 1858, Indiana.They are in Jefferson Co., IN 1880 census with son Nathan Cottom, 2.
They had another child, Nellie C. Cottom July 30, 1880.
Dayton, OH City Directory, 1898:Adda Cottom, widow of John, son Nathan T. Cottom and dau. Nellie C. Cottom.
Adda (Todd) Cottom signed for Nellie to marry William John Davis (1861-1936) July 4, 1898.
I cannot locate Adda (Todd) Cottom or Nathan Cottom after that time.Any help will be greatly appreciated.