User blog comment:IamJakuhoRaikoben/Chapter 392: I Must Not Forget, Review./@comment-49.150.151.110-20140712122353/@comment-7418318-20140715211308

Actually we don't know if Gray ever buried his parents. When Ul and Lyon found him he was unconscious.

If he stayed that way for a day or several, the bodies might have already been gone by the time he returned to his home-village. Gray would then probably assume that the bodies had been snatched by animals or buried in unmarked gaves by people who passed the town by.

Or he might not even have returned to his destroyed hometown. He could for example believe that a dead body is just an empty shell and thus doesn't require any special or deferential treatment. Or he's cold-blooded enough to just not care... he did just as good as murder his father despite knowing who he was after all.