It's been a couple of years and you've posted no update, so I'll assume you're still looking. A couple of thoughts.
(1) Where are HIS parents buried? Occasionally ashes were sent home and cremation was a way to lower the cost of it. I know it says "buried in Los Angeles" but plans sometimes change, and 1937 was during the Depression. He may be an added burial in a lot already owned by the family.
(2) Have you accounted for burial places of all of the children? Especially if a child died young, an adult parent could have been interred with them. This could be at a prior residence.
(3) Ditto with siblings &c. Sometimes a brother or sister, aunt or uncle will extend right of burial to a deceased sibling in a family lot. Find where all of his close relatives were buried. Use the 1940 census to help you here.
I wish you luck in your search. I looked for my own great-great aunt for close to thirty years, then found her by surprise...cremains buried, unmarked, with a son I'd never known she'd had, in the largest old cemetery in my own home town. It can happen!