I didn't find them prior to the 1910 Census because their surnames are very common and couldn't be sure I'd found your George and hester.
1910 Laurens, Laurens, SC
George B. Campbell, b. NC, 39, M2-2yrs, carder cotton mill
Hester, b. NC, 42, M2-2yrs, 4/2
Roy, b. NC, 10 [I think he was George's child but not Hester's]
I didn't find George and hester in a 1920 Census.
Possibility for Roy
1920 Lydia Cotton Mill, Laurens, SC
Joe Wofford, b. SC, 39, overseer weaver ___ ___
Minnie, b. SC, 37
Edith, b. SC, 14, spooler leather mill
J. L. b. Sc, 10
Raymond, b. SC, 5
Lester, b. SC, 2
Roy Campbell, sonlaw, b. SC, 21, weaver cotton mill
Hallie, Wofford's dau, b. SC, 19
George R. Campbell
Born: 1871, Spartanburg, Spartanburg, SC
Died: 1 Oct 1924, Laurens, Laurens, SC
Married Hester Campbell
Son: Roy Willard Campbell
Source: Cundiff Family Tree but no sources
I'd look up when South Carolina was issuing death certificates. I'd also contact the Laurens County genealogical and historical societies and ask if they have a local death index, obituaries and cemetery inventories. George's obit might provide clues about what happened to Hester. Successful Searching!