If time is of the essence, I'd say try to sell them as a single lot on ebay.
If he is trying to get the maximum dollars, sell them piecemeal. It might be good to get them graded through one of the trading card grading companies, if they are really in top shape (There are several companies around who will take trading cards and the like, seal them in plastic, and provide a neutral third-party assessment of the condition, so that a buyer can have confidence that the item is "as advertised". PSA and Beckett are the two that are best known. See HERE
for a discussion.)
Your friend might be wise to get a sample copy of The Wrapper
, an adzine for ephemera of this type. There are a number of dealers who advertise there who would buy them at a wholesale price, and then sell them one at a time at retail. Expect to get, at most, fifty percent of retail when selling this way (and probably less).
I would be surprised if he could get more than $10 each for them. If I had them for sale, I probably wouldn't accept less than $5 each, assuming that they are complete and are truly in top condition. (But he may be more motivated to sell than I am).
If he had a complete set, that would bring a premium from most buyers. A true completist would want each of the 24 different folders; each of the props; each of about 4 different wrappers (the differences were in the mail in contest advertised on the wrapper); the small poster of Blackstone that came with the original box; and an empty box. Richard's price of $250 for a set of folders/props from a couple years back seems reasonable; I think I paid about $200 for a set (less one prop) maybe 8-9 years ago.