I find in the obituary index the following Tibbals entries:
TIBBALS ELMER E. Pub date:11-29-1939 Col:5 Page:4 TIBBALS ROBERT (MRS.) Pub date:10-28-1920 Col:3 Page:1
This means that the obituary appeared in the Gladwin County Record.She apparently is buried in the Beaverton City Cemetery:
MARY S. TIBBALS (1873 - 28 OCT 1920) - Old Block # 2 Lot # 57.
MRS. ROBERT TIBBALS
Mrs. Robert Tibbals of Beaverton dropped dead of heart disease Thursday morning at an early hour. She arose in the usual health and went to the kitchen to light the oil stove and start breakfast. A half hour later she was found dead, not having lighted the stove. Gladwin County Record dated 10-28/1920 Column - 3 Page - 1
Also, while looking I found a cemetery reading from Beaverton City Cemetery that may be of interest to you: ALBENIA ANN (TIBBALS) SUGG (1907 - 20 MARCH 1957)