I searched the online databases, Ancestry and FamilySearch for Thomas and Maria's death info but didn't find it. There is a good web site, San Francisco Genealogy, www.sfgenealogy.com/ that you might want to look at too.
Don't forget about the earthquake and fire of 1908 when lots of records were destroyed.
The last census that I found them in was 1880 San Francisco, San Francisco, CA.
Dr. Thomas Green
Died: before Jan 30, 1887
Buried: Jan 30, 1887, Saint Mary's Cemetery, Oakland, Alameda, CA
Source: findagrave.com but I don't think yours was a doctor.
Birth & Death: unknown
Buried: San Francisco National Cemetery, SF Veteran tombstone, US Army
Source: findagrave.com. Do you know if yours served in the civil War?
1900 San Francisco, San Francisco, CA
Ellen Connolly, head, b. Ireland, 1869, widow, had given birth to seven children but only one alive in 1900, immigrated 1880
Annie R. Green, dau, b. CA Dec 1853, marr 29 yrs, had given birth to one child still alive in 1900,
thomas Green, b. Australia, 55, sonlaw,
Arthur C. Foley, adopted son, b. CA May 1890
1900 Napa, Napa, CA
thomas E. Green, head, b. Australia Dec 1844, marr 26 yrs, imm 1850, farmer
Maria A. Foley, sister, b. England March 1849, divorced, imm 1850
Earl T. Roney, boarder, b. CA March 1893
Vivian Roney, boarder, b. CA, July 1891
Alice Dolan, b. CA Aug 1885, neice
1910 Napa Napa, CA
thmas E Green, b. Australia, 68, marr 39 yrs, imm 1850, fruit farmer
Annie R., wife, b. CA, 49, no children
Annie T. Mullen, borader, 24
1920 San Francisco, San Fran, CA
thomas Green, b. Australia, 70, retired brewer
Annie R., b. CA, 58, no occ
Five roomers listed
I didn't find their death info either. If you decide you want to order a death certificate, contact the San Francisco County Reorder.
1900 San Fran, San Fran, CA
Joseph C. Green, b. Australia, 50, 1850, imm 1883, engineer
Irene, wife, b. CA Jan 1857, had given birth to nine children but only six alive in 1900
Charle, b. CA Nov, 1886
Irene, b. CA, Aug 1889
Amelie, b. CA May 1895
Raymond, B. CA Dec 1897
Mary Sumner, lodger
I didn't find death info for Joseph either.
1920 San Fran, San Fran, CA
Irene Green, b. CA, 67, widow
Raymond, b. CA 22, accountant tobacco co
Robert, b. CA, 19, collector real estate
Marie Lenorman, dau, b. CA, 42, div, button & badges printing office
Raymond Lenorman, grandson, b. CA, 17
1940 San Fran, San Fran, CA
Charles paulson, head, b. CA, 44, education=8th grade, bookkeeper petroleum
Emily, wife, b. CA, educ=high school 4 yrs
Dorothea, b. CA, educ=high school 4 yrs, stenographer life insurance
Irene Green, malaw, b. CA, educ=high school 1 yr, 1935 was living in San Anselmo, Marin, CA
Irene L. Barut Green
Born: 13 Jan 1857, CA
Died: 21 Oct 1946, San Francisco County, CA
Source: California Death Index 1940-97.
You can contact the San Francisco Public Library, http://sfpl.org/index.php?pg=2000001701http://sfpl.org/index.php?pg=2000001701 for a copy of her obituary.
The last census that I found Maria Green Foley was the 1900 Napa, Napa Census.
I didn't find anything for Delia after the 1880 San Francisco Census.