Collision center at the dealer drove mine about 300 miles in 5 or 6 days. Contacted the Body shop manager, customer service dept at the dealer, and the BBB; nobody cared. Mileage was listed on the in paperwork from when I had the insurance inspection (earlier that day) but not the out paperwork when i came to pick it up. When I went to pick my car up my trip odometer had been reset (purposely left it and noted it to check miles) and so I recorded the odometer on video to prove mileage, and I sent it in to the dealer. They told me that nobody drove my car and thats all there was to it. BBB said it fell under punitive damages and that they wouldn't consider it.
And this was at the body shop! my car should have never left the place under any circumstances. Anything your friend attempts is going to be a waste of time. What does he expect to get out of it though? I get that he feels violated; I was furious. But what is 90 miles over the life of his car?
If it was part of some 'diagnostic procedure' (even something silly like you have described), thats even more power to them.