If you are not already aware of it, you should see the story of the Armstrong's on pages 13-20 inclusive in the book "The Valley of the Dinosaurs - Its Families and
Coal Mines", by Ernest Hlady, published 1988, ISBN 0-88925-836-8. Includes a family tree, photographs, etc. With the information from this story and online telephone books, you should be able to find several relatives in
Drumheller and elsewhere. I see that there are several listed at
Drumheller