Passport - check
Easyjet boarding passes - check (he's going to get a shock when he goes on Easyjet!)
Printed hotel confirmation - check
Euros
Eurocard
He's 17. He's been to the States with this friend before when they were 15 with no adults around, and chose this mate because he knows they won't fall out.
Should he take anything other than the above and a few t shirts and shorts?