I'm speaking specifically about Wordpress here, but I know there are plug-ins for Wordpress that enhance
SEO. Has he had his blog for a long time? In
SEO terms, there's a lot of value in keeping a site or blog that has been indexed for awhile and has been consistently updated. When you start changing things up or start over, you sort of lose that history. Also, if you put some work into it you could make a blog look really great and have it function as your website as well (saves time vs. updating both a website and a blog).
BUT...I think that both you and Michelle are correct in that the prevailing thought is that you should have a blog within your website if possible. Just giving some other thoughts to add in the mix...
Angie