I can't tell you definitely. The Malaer Family Tree says he married Crawling Ivy who was born abt. 1820 in Seminole Co. Florida and died abt. 1889, Johnson Co. IL. I can't find a Crawling Ivy Malaer or Ivy Malaer on any Census.
You might have to look through every Census for Johnson County looking for a Ivy Miller. I think Malaer was probably written down incorrectly as Miller.
John died 5 Nov 1859 in Johnson Co. IL according to Grill Family Tree.
The Johnson County Illinois Genealogical & Historical Society, http://johnsoncountyil.net/
might be able to look up more info about John. Successful Searching!