The starting published rates are in the $500 range, but not for a solo traveler.
I am booked on the Spendor in May, in a cat 1A. It's $823 without taxes.
I don't think he will get it much cheaper as solo, however if he has a roommate, that will make a difference.
I wouldn't chance it. The fuel surcharges have been lifted for now, but if he waits, they may be reinstated, which will increase the price. You need to pursuade him to put down his deposit now.