It probably is Warner, that is a family down that comes down from one of the early wives, Sarah Warner wife of David Hayhurst.Go to the box that says search this forum, type in Warner and you will find lots of people working on Hayhursts with Warner as part of their name.My husband's Joseph Warner Hayhurst was down in TX.
Have you looked for a Warner Hayhurst on the 1900 census to see if he has a son named Louis about 4 years old?Then follow them through 1910 and 1920, it might give you an idea of where they were living when they passed away.
SSDI (Soc Sec Dth Idx):
Louis Hayhurst, b 17 May 1896; d Sep 1962; last residence OR; SS card issued in Montana.
Have you obtained a copy of his death certificate?It should show thenames and birth locations for his parents.Or, if the informant did not have that knowledge, he filled out his own application for a Social Security number, and you can obtain a copy of that application -- it should show his parents names.