Hi Barbara, Have you contacted the Harris County, Texas Clerk's Office? Perhaps they can provide you with more information about Bertha's death.
I searched through her parents and siblings thinking she might have returned to live with them, but didn't find her there.
I tried to do the same with Roscoe's family but couldn't find where they were all listed on the same Census.
I also found two Family Trees on www.ancestry.com with your family members. You might want to contact these two potential cousins and see if they have any info they didn't post of their trees.
I did find that Roscoe William Robertson was a Surfman U.S. Coast Guard World War I. Born=21 March 1888, Died=1 March 1964. Service Start Date=1 April 1917. Interment Date=4 March 1964, Golden Gate National Cemetery, 1300 Sneath Lane, Section 2C, Site 3967, San Bruno, CA 94066. Source: U.S. Veterans Grave Sites ca. 1775-2006, www.ancestry.com. Successful Searching!