Hatcher took her data from the DAR listing. The data may have been provided by a local chapter's list. It might be more productive to contact the nearest chapter to the gravesite to see if they have any info. Since the findagrave listing does not mention a DAR marker, the chapter itself did not have the grave marked based on something they knew. This is curious.
One of my ancestors' gravestone had a DAR marker whomped onto it despite there being no DAR member in the local chapter who was a descendant of his, and there being no proof of his having been a patriot (oh, his common name is on a militia list, but there's no further evidence connecting my ancestor to that list). Queries failed to turn up any information as to how the chapter came to install the marker. It's a bit mysterious.
I hope the process of your man's entry's landing in the Hatcher book is more straightforward.