It looks like Charles is the son of Richard and Frances Widga. Richard and Frances are buried in the Stromsburg Cemetery, as is Donivan. I have photographed the entire Stromsburg Cemetery and put it on Findagrave.com.
I live in Polk county and am willing to help, but I need more info on what specifically you might be looking for. I could look for an obit, a marriage license, etc. This Charles Widga is not buried in Polk county, so he is probably buried in Arizona as you suspect. Good luck and let me know if you want me to look for something here.