I have found the death certificates on Daniel K and Eliza J.
Daniel K. died in Dover, Kent Co, DE on January 01, 1915
Informant Ms Reeder of Dover
Eliza J. died in Dover, Kent Co, DE on 21 Jan 1920
Informant Park M. Reeder of Washington DC
Both bodies were taken to Washington, DC for burial.
They are now available in electronic form at the LDS site and in Ancestry.
On Daniel's DC it is indicated that his parents were John Reeder and Sarah Jane Anderson both born in Germany.
The census records do not support their Germanic birth but it is probably another generation back that it is.