I suggest looking on familysearch.org
Just put in the name Edward Dunn and see what comes up. If you are lucky, you might find a marriage if he married in the United States and then you will know where he went to.
Also, try roostweb, just look under familytrees. Put in his name and see if anything comes up.
Best wishes in your search and I hope someone related to your family see your post.
http://familytreemaker.genealogy.com/users/m/c/g/Val-Mcgrath-Qld/WEBSITE-0001/UHP-Surnames.html Try that website
I only found this Edward Dunn, states he was born Victoria Australia and his occupation was an electrician. Might be worth following up.
Canadian Passenger Lists, 1865-1935
Name: Edward A Dunn
Gender: Male
Age: 22
Estimated birth year: abt 1887
Date of Arrival: 9 Mar 1909
Vessel: Makura
Port of Arrival: Vancouver, British Columbia
Port of Departure: Sydney, Australia
Roll: T-4861