He may 'Want' to use his credit card, and I can understand that with cash being tight here this month too! But I don't think they will be allowing them as too much chance of them being bounced, refunded, etc which is why they do state debit cards only on the payment of balances so I can't see it being any different on resale day.
Imagine it, you get lucky enough to get through to the booking page where you can add your payment details & then get bounced out because it won't accept CC's? Would you risk that disappointment??
Good Luck for yr mate anyway!