jlh1603 on Family Tree Circles

My Great Grandaunt, Katie McDonald, is one of several mysteries in our family. She supposedly served overseas as a nurse in WWI but no one knows if she served with the Canadian or American military or another nursing unit. Katie (Katherine or Kathleen) was born on February 18, 1891 in Alder Point, Cape Breton, Nova Scotia. The family story, as I've heard it, is that while she was serving overseas, her father, Angus MacDonald, passed away but no one told her until she returned after the war was over so she left Cape Breton, went to Boston and never contacted the family again. The only problem with that story is that her father passed away in 1911. There is no record of a marriage in the family Bible and no other information pertaining to where she went after leaving home, either before or after WWI. I'd love to know if a professional genealogist could help me to solve this family mystery. Thanks!