Looked at the online Detroit Free Press for August 10, 1943 on page 22 and there was a Morrison but it was Thurman. The search for a Sarah Morrison showed results for a Sarah and a Morrison but no Sarah Morrison. Looked at August 4 through August 8 and did not find a death notice for her.
Did you notice the option to have your local library borrow the films from the Detroit Public Library instead of paying them to look for her obit/death notice? THere were three newspapers in Detroit at that time. I think the Detroit News was the largest and her death notice may be in that newspaper. The Detroit Times seemed to be the smallest of the three.
If you live in the Lansing area, the State Library of Michigan has the Detroit newspapers.
Or try the Detroit Society for Genealogical Research to see if they could get the obit/death notice for you. dsgr.org