Sayid, et al dug up the hatch-captive's "wife's" grave and found, instead, the body of a man. The man had a Minnesota license with the name the hatch-captive claimed to be.
I.e., hatch-captive, just when you're starting to trust him, is probably -- almost definitely -- an other.
(You could have just asked this in the Lost thread.)
EDIT:
Originally Posted by EW.com
...all is not as it appears, of course, and — here's the climactic reveal — the body in the grave is a man's, not a woman's. The man has a driver's license. The driver's license belongs to one Henry Gale, an African American from Minnesota who looks not a thing like our Henry. The jig is up.