But you'd have to do that for each brand that he sells. It's not the DecorMyEyes keyword that people are getting the "wrong" result for.
http://www.google.com/safebrowsing/report_badware/ http://www.phishtank.com/ http://toolbar.netcraft.com/
EDIT: You can also report them to McAfee Secure and Authorize.net. I don't think they are happy about having a scamming merchant using their logos.
If this had happened to me it would have actually been enough to make him my new favorite target. Judging by a quick purview of the source of his page it probably wouldn't have ended up pretty well for him either.