I Have Reached a Dead End on My Paternal Grandparents John Vester West and Mina F Thomas West IN IL

He appears in the 1920 Census as being one year old and listed as one of the children of John Vester West and Mina Thomas West. My father was born in 1913 in Vermillion, IL. There is a picture of "Billy" as a baby in a photograph of all the brothers. However, after what I found in the 1920 Census there is no other further mention that I can find of him. No one in my family ever mentioned him. My Mom and Dad were married over 56 years and they grew up in and around Mattoon, IL. She is now 91 and said that she does not remember anyone ever mentioning an additional brother other than Archie, Sam and Frank (my dad).