He was not listed with Joshua's family in the 1880 census but there was an Albert C Harris, son of Andrew and Lovina, next door who was the right age. Could he be a nephew who was taken in by Joshua after his parents died?
If Albert had a son in 1918, he must have had a first wife.
Residences & events:
19/?/1930 Mattoon, Coles Co, IL. The census that year recorded Albert at age 53, Maud at 44. They must have misunderstood the question as the census says Albert married for the first time at age 51, Maud at 42, but since she had a 17 year old son, they must have married each other at those ages. Living with them was 17 year old step-son Noel Hunt. Albert was a laborer in public service, Maud worked as a restaurant waitress, Noel was a carpenter in a trellis factory. (Where was son John?)