The 1900 and 1910 censuses show Annie married but apart from John. She was born Feb 1854 in PA. The 1920 census shows her as a widow. The 1900 census shows Harry Holtzman, born July 1836 in Washington, DC, married 25 years and living with his son John in Bonhomme. His parents were born in PA. I could not find him in the 1910 census.
I could not find Annie's death certificate. Perhaps she remarried.
The 1870 census of Jacob H. Holtzman in Bonhomme seems like it could be him.
It would seem John was John Harry or Harry John. Harry was commonly used as a nickname for Harrison.The 1860 census of Washington, DC includes a John Holtzman born ca 1833 and a Harrison Holtzman, born ca 1837. No one listed seems to be the parents. The former seems to have stayed in DC, while Harrison disappears altogether. I suspect that is because he went by Jacob, Harry and John in later censuses (in other words he could be your John).
Not having an exact date of birth and conflicting data does not help. I suggest contacting the cemetery where he is buried to see what they may have in their burial records on him and if he has a tombstone what birth date is on it. His obituary may help even if it only lists any surviving siblings. It might also indicate if he served in the Civil War. If so his service record and any pension may have some helpful data.