Bonnie, I am not related, just did a couple searches for you.1920 census shows Claude Smith age 72 b. Indiana, Jennie S. Smith b. KY, son Frederick Smith age 47 Dentist, b. KY living in the household you provided.
Cal Deaths shows:
Smith, Fredb. 09 Feb 1872, male b. KY, mmn Sheppard, father: Smith, d. Orange County 11 March 1941 at age 69.
Based on his mother's middle name being "S" on the 1920 census, I would think this is the Frederick Smith you wrote about.
Have you obtained his death cert or obit from Orange County to see if his sister possibly reported his death?Just a thought.
If you go to www.mapquest.com and run 114 Buffalo, Santa Ana, CA it shows a map with 114 W. Buffalo Avenue.I am not sure if the home is still there, but the address shows as a good address.
I may have time next week to do a "drive by" of the address and see what is there, if you would like me to.Pls email me at email@example.com if you would like me to do that.