It's kind of you to post this info. I'm not related to this particular family but I believe they are listed living in Detroit in the 1900 census as follows:
Robert Dickson, head, born Feb 1857, age 43, md 22 yrs, birthplace Scotland, occ. Plumber; Marie, wife, Nov 1853, 46, md 22 yrs, gave birth to 9 children with 7 living, birthplace Germany; Alexander S., son, Feb 1878; William S., son, Apr 1881; John W., son, Nov 1883; Emma J.E., dau, Mar 1890; Marie Edles [spelling?], mother-in-law, birthplace Germany.
Douglas wasn't listed with them in 1900 so likely he was living elsewhere as were the other two living children.