That's probably not too far off. In taking part of many buy/sell threads at the corvetteforum, I see a lot of depreciation for the resale of parts. Granted, these look new, but the $2200 price might not be the lowest.
Another thing to consider is any problem can be taken up with a seller while "used" items are sold as-is. That's a big reason for drop in value.
Another is possible age. Typically, people consider tires good for something like 3-6 years because rubber gets harder with age -- and the tires lose performance.
The Corvetteforum has the most traffic that I've seen but people sometimes put Corvette wheels on other Chevy vehicle. List them in your local Craigslist -- with the bolt-pattern and offset. You might get a non-vette owner wanting to buy them.
My guess is they won't go for more than $1500. Even then, I might be optimistic.
Maybe it would be cheaper for your friend to buy another Corvette!!! Keep in mind those C5 wheels will fit other generations. So post in forums for all generations.