And it isn't a filter, I rebuilt the database already. Three other machines, one another Entourage client at his house and one a Blackberry and one is Outlook 2007 - all show the "missing" email. I have tried resyncing, etc. Just can't figure out what happened that is creating the discrepancy on this machine.
Solved. I deleted his account settings completely (of course it warned of the dire consequences of such an action as it would delete all mail - locally only of course), manually set up his settings again, since the automatic never works. And when it finish, magically all email reappeared.
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