Hi Wendy, I hope you already found this information. However, if you haven't, I searched for Albert and Gladys Lillian death dates in Ancestry, FamilySearch and Findagrave but found nothing.
Are they mentioned in Gladys Marie's or Albert (b. 1917) obituaries?
Albert and Gladys (parents) were living in Willows, Glenn Co., California on Sept. 12, 1918. Albert Edward Cavanaugh Born: 16 July 1885 Occupation: Cement worker for Ed Nelson, Willows. Nearest Relative: Gladys Lillian Cavanaugh, wife who lived in Willows too. Source: World War I Draft Registration Cards 1917-1918.
A Gladys M. Cavanaugh Born: 11 Aug 1918, San Francisco Co., CA Mother's Maiden Name: Spiering Source: California Birth Index 1905-95.
But then her death info is Gladys Marie Cavanaugh Born: 9 Aug 1919, CA Died: 29 June 1994, Los Angeles Co. Mother's Maiden Name: Siering.
I thought we might be able to figure out where Gladys (mother) died based on where Gladys (dau) was born.
You can contact the San Francisco Genealogical Society, californiaancestors.org/ to find out if they have death info on Gladys (mother). Death records were required starting in 1906 so it should be somewhere.
You'll find more info about death records in San Francisco city and county at sfgenealogy.com/sf/sfranvit.htm .
There is also a death index volunteer at Random Acts Genealogical Kindness. Go to raogk.org Click on California Click on ALL for county name and choose Brenda.
The Glenn County Recorder's office can be reached by a Google search or 530-934-6305. Successful Searching!