Greg
You know he was born in 1871 and died in 1938
Wasylija HRYVNAKA is on his tombstone written in Rusyn so in English it would be Wasyl HRYVNAK / HRYWNAK ?
In Poland, Podkarpackie wojewodztwo HRYWNIAK most in and around Sanok.
http://www.moikrewni.pl/mapa/kompletny/hrywniak.htmlHow to find anything about him.
He should show up in 1930, 1920, 1910, 1900 census depending when he came to America.
Sometimes a draft registration form will have a place of birth.
Maybe he was naturalized citizen?
You might check into the church where he was buried from.