I found the family in question in the 1900 census. The mother's name appears to be Mary, not Martha (as Grace's obit says), which is confirmed by the 1880 census for her family: daughter of James and Martha A. Spencer.
1900 U.S. Census, Washington, Chehalis County, Aberdeen (ED 7, sheet 14, line 57) 16 June 1900
Hembling, S._., b. Mar 1858, 42, married 14 years, born Canada, parents born Canada, immigrated 1879, in U.S. 21 years, carpenter, owns mortgaged house
Hembling, Mary, wife, b. May 1868, 32, mother of four children, four living, born Oregon, father born Missouri, mother born Canada
Hembling, Magdalene, dau., b. Jan 1889, 11, Washington
Hembling, Grace, dau., b. Aug. 1894, 5, Washington
Hembling, Walter, son, b. May 1893, 3, Washington