If this individual is not a user of the system (ie. cannot log in), then FogBugz will not automatically send him any emails unless you explicitly tell it to. To do this for a particular case, click the "Email" link on the case details page and you should be shown a basic email form with the case correspondent already set in the To field.
The reasoning behind the decision to not automatically send case event email to correspondents is that a correspondent is typically someone external to the group or organization that is using that instance of FogBugz and there may be internal information that they should not see. Making sending an email to correspondents a human-driven thing helps to make sure that people are getting appropriate information.
If, however, he isn't receiving any emails at all, including those sent via the "Email" link on a case, I would suggest getting in touch with FogCreek directly either by email or by phone (see the footer of this page for the actual contact info)