Do you know anything about Wade and Stella?If your father's birth name included Edington, and that was Stella's maiden name, sounds like a family connection, maybe Stella was his aunt(?)
Do you know when and where Wade and Stella died?Obituaries might list survivors.
Are his birth parents listed on his birth certificate?Have you tried tracking them?
Combined info from TX Dth Idx Online and SSDI:
Stella Elam, b 24 Jun 1908; d 7 Jun 1984 Tarrant Co, TX; last residence and benefits Fort Worth, Tarrant Co, TX; SS card issued in TX.
This Stella would be only 13 years older then your father, but she could have been a younger sister of his mother.The Fort Worth Public Library has a good genealogy collection, maybe they have local obituaries in their collection.
Check Tarrant Co, TX GenWeb site, some GenWeb counties are putting their cemeteries online, see who is buried with this Stella.I'm sure there will be some mention of the public library, maybe an email or online catalog.Happy Hunting.