Surrogate court records can be consulted at the Archives of Ontario (in Toronto, Ontario). If you are not sure where your family member died, you may want to consult the MS 404 microfilm series. This series of microfilm is a register of all wills til 1982.
Dufferin County Estates Files at the Archives of Ontario (MS 887 series)
The following publication can be found at the North York Public Library or at the Archives of Ontario:
Gibson, June. Surrogate Court Index, Canada 1859-1900: Volume 18 Dufferin County. Agincourt: Generation Press, 1990
Last updated: June 26, 1999