Here’s the information you requested. I have sent some additional information because of the relationships.
From Cemeteries of Brown County, Illinois
Mt Sterling City Cemetery, pp. 229, 261
Jonathan, son of S. Douglas and M. Nichols, 7 Aug 1880 – 8 Jan 1898, grandson of John J. Nichols.
John J. Nichols d. 4 Jul 1904
John Nichols, son of John J. Nichols, 17 Jan 1894, age 51 y.
No additional information on S. Douglas or M. Nichols. If it turns out that this is your Douglas S. and Mary Nichols, let me know and I’ll write it into the Cemeteries book for future reference.
Would you please lok up for in the BrownCounty Cemetery listing my grandparents, douglas S. Nichols and Mary Nichols ( Harman). thank you for your trouble. Barbara Willson