DuLac appears to be a prevalent name in France, Canada and upper Minnesota and NY.
Many times dreams are a part of the entirety of things we have been exposed of recently, or many years ago in life.
The dream is a combination of many many things.
Looking at your dream I would say that your husband had recently seen some type of show about the English (Red Coats) or the Canadians (even Mounties wear that type of coat) and possibly in a movie or book he had read about this Godfrey DuLac, or his mind may have remembered books he read as a child which had many many illustrations by a DuLac.
There is also a DuLac Wisconsin, I believe.
I personally am searching for DuLac persons in Canada and upper USA since my friend is a DuLac and has never traced his family tree.
I am specifically looking in the Columbia Heights (Minneapolis), Minn area.
Sorry I can't help you, but I am sure it was just a compilation of things he has seen or read in his lifetime or not long before his dream.