William Cummings married Caroline Brown of Carroll County IL in 1853. He had a younger brother David born circa 1834 in NY or MI, and probably other older siblings living in 1850 in Carrollton or Mt. Carroll IL. The David in this family may be too old for the David Daniel Cummings you are looking for, as that David shows up in Branch Co MI census through about 1870, not in IL. William's father was also named David. It is possible that the David you want is a son of one of the other William Cummings siblings, and the grandson of the senior David Cummings and his wife.

This is my husband's family.

Susan Cummings