Yes.

But you're missing a step.

You would right-click on your INBOX and give Reviewer permissions at that
level in order for him to read the e-mails.

At the top MAILBOX level, you would add him the permission list, but not
necessarily assign him any 'roles" - just make sure that "folder visible" is
checked. This allows him to view past the top Mailbox level, down to the
INBOX level, where you set his viewing permissions.

Tracy