Hi Debbie, Regarding the indepth info from U.S. National Homes for Diabled Volunteer Soldiers 1866-1938, when that appeared for Otis I clicked on the View Original Image.
Sounds like you still are unsure about where he died. It looks like the military info says he died in Yountville (which is in Napa County). You can ask the Napa County Recorder-Clerk, countyofnapa.org/Pages/Department.aspx?id=4294967365 to search for his death certificate. They will charge a fee.
Sawtelle is located in Los Angeles Co. The Los Angeles Recorder, lavote.net/recorder/BDM_Records.cfm has copies of death certificates. They will charge you a fee too.
Another way to confirm where he died is by finding his obituary.The Napa City/County Library, countofnapa.org/Pages/Department.aspx?id=215 .
OR Napa Valley Genealogical and Biographical Society, napavalleygenealogy.org/ . They charge a fee.
Trying to find an obituary is Los Angeles Co. is like trying to find a needle in a haystack. I can provide clues if you need to go that far. Successful Searching!