I can only find a couple records mentioning his father's name that I'm confident are referring to the same Eraste Guillory:
https://www.familysearch.org/ark:/61903/1:1:FS1P-8B5
https://www.familysearch.org/ark:/61903/1:1:FS1G-G44
They both call his father "Sestian", but every family tree calls his father "Sosthene" and links these records to him.
If this is his real father, then Francois Guillory (1815-1855) is probably his grandfather.