Good day Fran, I may be able to help you. I believe the Alfred Dempsey is the ggrand father of a friend of mine. I emailed him your request and I will ley you know if it is the same person.
By the way he is in Sudbury.
Go to this web site
http://www.rootsweb.com and family trees and type in Thomas Dempsey and the one married to Laderoute should be what you are looking for