I don't have this John Theal in my tree, but do have a John G. Theal, b. 15 May 1912 in Los Angeles Co., CA; d. 02 Jul 1969 in Ventura Co., CA. His father is Leo Theal, b. 05 Jan 1885 in Wentworth, Ontario, Canada; d. 28 Jan 1952 in Los Angeles Co., CA. His mother is Julia Townsend (Gee) Theal DeSoto, b. 04 Oct 1891 in California; d. 19 Apr 1974 in Oxnard, Ventura Co., CA. Julia is my second cousin 3x removed and is buried with her second husband Virgil Milton DeSoto in Golden Gate National Cemetery, San Bruno, San Mateo Co., CA. I don't know if Leo Theal might be related to your John Theal in some way or another . . . this is the only information I have on this family.
Anna