Obituary for Wenzel's wife:
Clark County Records (http://www.usgennet.org/usa/wi/county/clark/clark/data/2/bbs58/58322.htm - broken link)
Where she is buried:
Clark County Records (http://wvls.lib.wi.us/ClarkCounty/clark/data/2/bbs58/58321.htm - broken link)
Wenzel died in 1954:
St. Bernard's Cemetery Index KL (http://wvls.lib.wi.us/ClarkCounty/cemeteries/withee/bernard/index/KL.htm - broken link)
There are no names in the cemetery index that look like Carl.
Joseph's obituary:
Kunesh, Joseph (1883 - 1909) (http://wvls.lib.wi.us/ClarkCounty/clark/data/obits2/2012.htm - broken link)
I doubt he came to the US in 1866, since he was not born then.
Wenzel and Marie are in the 1930 census for Thorp. He is an engineer. The country of origin is listed as Czechoslovakia.
Since you have an address, you might contact the library in Thorp and see if they have a town directory for 1914. You may be able to find Carl that way. If he owned the property, he should also be in the property deeds and tax info.
THORP PUBLIC LIBRARY