I think you're going to enjoy this? You may have gotten better responses by posting in Walker County? That aside, you'll receive help 'cause that's how genealogy is researched in Texas. There is a family tree but the owner has chosen to keep it "private". That's okay 'cause you can experience the surreal feeling of finding ancestors. If you do not have an account with https://familysearch.org/
please open one? It's free and necessary to access vital records. Your grandfather had ten siblings and he appears to have been the middle child, number 6. Annie Willis wed "Premus" Ross, 18 Dec 1895, per familysearch. Same database has death certificates for both: Annie Ross (1 May 1876 - 18 Aug 1962) and Primos Ross (17 Feb 1876 - 17 Apr 1942).