Hi Marsha, The challenge in Orange County is that it's a very large county with many towns, cities and newspapers. It's difficult to find an obituary in this County.
The California Death Index told you where he died but didn't mention the city. The Social Security Death Index says his last residence was Laguna Hills but that info isn't always correct. The Soc. Sec. uses that field for other purposes.
However since that's all the info we have, let's start with it. Contact the Orange County Public Libraries, http://egov.ocgov.com/ocgov/OC%20Public%20Librarieshttp://egov.ocgov.com/ocgov/OC%20Public%20Libraries Click on Contact Us Click on any link of the five top managers Then your request will be sent out to the appropriate library.
If they can't find his obituary (which should contain info about the cemetery), you can order a copy of his death certificate which will have the Residence field in correctly if the Informant was knowledgeable. You can order the death cert. from Orange County Clerk-Recorder, http://egov.ocgov.com/ocgov/Clerk-Recorderhttp://egov.ocgov.com/ocgov/Clerk-Recorder . His burial location might also be on the death cert. Successful Searching!