The 1920 US census shows the following family in Canton, Fulton County, Illinois

Rowland A Turner 34
Emily 33
Olive 10
Marjorie 7
Corrine 5
Harriet 2 6/12
William 1/12

William is probably the nephew you refer to.

SSDI shows Rowland Turner born May 24, 1884 died Jan 1965

There are presently five Turners in the Canton telephone directory. A letter to each of them might prove helpful