I think any CC company would have a difficult time justifying giving someone credit without any income.

Remember, you don't necessarily need employment to have income (however I think AMEX prefers employment). If your friend's parents support him (an allowance), that is considered income. As well as scholarships and other sources like that.

However, unless he generates some form of employment on his own I think AMEX (of any kind) is out of the picture for now. He would probably have a chance obtaining a student credit card from another company.