Hi, I did a Google serach on Mahoney Mortuary Sunnyvale California but it wasn't listed on the results page. I'd say they're out of business.
Funeral home records aren't always archived. Sometimes the owner gets rid of them. However, they might be at the Santa Clara City Library Genealogy Collection. There's an article at http://library.santaclaraca.gov/index.aspx?page=1170http://library.santaclaraca.gov/index.aspx?page=1170 which talks about their holdings.
You can also contact the Santa Clara County Historical & Genealogical Society, http://scchgs.org/http://scchgs.org/ .
You can request a copy of Frank's death certificate by contacting the Santa Clara Clerk/Recorder, sccgov.org/portal/site/rec/agencychp?path=%252Fv7%252FCounty%2520Clerk-Rec ...
You can look up his obituary at the Sillicon Valley Library System Reference Center, http://obit.systemref.orghttp://obit.systemref.org .
OR Contacting the Santa Clara County Historical & Genealogical Society, scchgs.org/main/service.html .
You can also request the microfilm via inter-library loan. Successful Searching!