Exactly - email will not be scanned
He can configure the email account as avast is not there, the 'right' settings.
Then, close the email program (Outlook Express) and go to Start Menu > avast antivirus > Mail Protection Wizard.
Run, follow the screens, finish the wizard.
Open the Outlook Express and check the settings if they're correct.
I am not aware of any spam killer app on his system. Why do you ask?
Because some of them change the server/account settings like antivirus in Windows 98.