I am unsure if this info would be of any help- it may provide a lead. I have
a copy of a newspaper clipping (unknown source) that was printed in 1909,
somewhere in the Orkneys. The article is in honor of Robert Sinclair's 50th
anniversary. It mentions a brother Alexander who had settled in Galt. Robert
was born 1837. Could Alexander be Duncan's father? It's a long shot but
maybe??? The article does not refer to Alexanders age or children. Maybe
this would help?? Marilyn