You'll notice that is syncing through the cloud. i.e. from Outlook to Windows Live (that's like Microsoft's iCloud) then from Windows Live to the phone.
It's not the worst thing in the world. Actually what you end up with is a better solution than direct Outlook to phone syncing.
From memory you have to associate a Windows Live ID with the phone. Your mate could just use that Windows Live ID to sync contacts and calendars and then use his own email account (whatever that happens to be).
On that note, who is your mates email with? (e.g. gmail, yahoo, hotmail, company owned, ISP etc?)