Hello, My Grandmother was Rose Deighan White. Rose was Harold Deighan's sister. Harold and Rebecca were the parents of Robert Oldcorn who as you said was an orphan raised by his Oldcorn grandparents. I also know from my mother that Harold's mother provided financial assistance and had Robert secretly baptized in the Catholic church.
I have a picture of Harold Deighan taken before he left for WWI with his comrades and also several letters he wrote to my grandmother Rose while at Fort Gordon in July 1918 before he left for France where he died in October ? 1918. Also many letters Rose wrote trying to find out how Harold died.
I saw a post from Alan Deighan who said his father's father was Robert Oldcorn...did Robert change his name to Deighan at some point?
As you know Rebecca and Harold never married I believe Rebecca died of the flu but it was later than 1917 because by family lore Rebecca revealed Robert's birth to Harold's mother after he had died in WW1...Feel free to contact me. My mother, Rose's daughter is in her 90's and also knows some things. Such a sad story for these young lover's and the child who never knew them.