First I'm not related, just intrigued. Seen you have been trying for a few years with this family and thought why not play around to see if I might be able to find something.
Here is my thoughts.
Fredericks wife died in 1911, meaning Fred was about 41yrs old. In this time frame, not many especially with children stayed single for very long..
1) so did Fred get remarried?
Finding this could help you find him in the census which are now free access at www.familysearch.com
along with many many other records.
2) in the 1910 census in Ogemaw Co, states Fred and Maggie had a son Fred age 1. Found on www.familysearch.com
again a death record in Massey, Sudbury Co, Ontario for a Frederick Marden 9yrs old est birth 1910 whom died on Jan 15, 1919 parents stated: father Frederick Marden, Mother: Margaret Evart.
3) I would suggest contacting a library in that area for an obituary on this child, it would hopefully state if parent was living there to or if the child was living with another family member - a new lead. Their website is: http://www.sudburylibraries.ca/en/booksmuchmore/genealogyloc...
4) follow the links to the library above and you will see other resources for the area.. they might be helpful too?
5) Since this young child was in this Ontario area, then did the father and some siblings stay there? This might be an area to look for Fred's death in 1951 or search the same cemetery where the child is and you might have the fathers death information there too???? Here is the site I found the childs headstone, suggestion, contact the cemetery, just because there is no headstone for the dad doesn't mean he's NOT there.. http://freepages.genealogy.rootsweb.ancestry.com/~murrayp/su...
Okay I'm done for now ;-) This should give you a couple ideas on where to go, especially since some of your family came from that area in Ontario in the first place,