They're rare enough that the market seems to shoot up and down a lot, and of course custom colours = $$$ but from what I see them listed at on offset they're worth around the sort of price your friend is asking. I could see anywhere from $1800 to $4000 with the top end being something like a mint IBM, Sonic Blue or Inca Silver and a good sunburst getting $2750 or so.
Those numbers are mostly guesses but based on looking at a classifieds ad every now and then.
This is one of those guitars that was a commercial flop, but is so rare that the prices are usually artificially high. Kinda like the Coronado or Starcaster, though you can usually find Coronados cheaper than XIIs while the Starcaster is the most expensive. I would love to have all 3 guitars, but I would chunk out the money for a Coronado or Starcaster before I would for the XII. It is the coolest electric 12 string out there ( Taylor T5 -12 is pretty hot)