This is what I've figured out since my last post about this family.
William P. Caudill's wife is Mary Margaret Hoops d/o John Henry Hoops and Frances Bowling.William's mother is definitely Isabelle Unknown Cordle Elswick.She is living with him in the 1920 census.
William's mother is Isabelle and John and James' mother is Lou.They are two different women as Isabelle is living with her husband John Elswick on the 1910 census and Lou is living with John and James in 1910. I don't know Isabelle's maiden name yet. I have tracked everyone living next to these 3 brothers on the 1910 census in Tazewell and figured out where they belong........except for John Walter Caudill.
I also learned that John Walter Caudill was an illegitimate child and raised by John Caudill and took the Caudill name.He is a Ratliff/Asbury.Mary hoops descends from John Ratliff and Charlotte Rose Asbury.I know he has to be connected to William since he's living next to him but I just can't figure out the connection or who "Lou" is.