Found a death record for John Eighner in the WPA death index. He died August 29, 1918, age 92, in Fairfield twp. - rec. bk. S-15L, pg. 149. You can write the Tippecanoe Co. Health Dept. for his death record.
http://www.county.tippecanoe.in.us/departments/health/

There is an index to the Lafayette Journal and Courier Newspaper on the Tippecanoe County GenWeb site and the following Eighner's are found in it:

Eighner, Frank - Found dead - 3 Jun 1938
Eighner, Mrs. Nettie - d - 25 Feb 1932

Microfilm of the newspapers are at the Tippecanoe County Public Library: http://www.tcpl.lib.in.us/