How to negotiate with a bank on an upside down auto loan?

I am asking this on behalf of a friend I want to help. He’s upside down on an auto loan and really needs out of it. The loan balance is $28,000, the car is worth $20,000, his monthly payments are $483/mo plus comprehensive insurance of $111/mo. I was thinking he should approach the bank who holds the note and ask them to allow him to sell the car himself, release the title, and then refinance the balance owed. How can he best convince the bank to do this? Isn’t it in the banks best interest to do this? He can make monthly payments of a couple hundred dollars a month. He has a decent job, but unfortunately his credit worthiness and credit scores are not as good as when he first got the loan. But at this point, it doesn’t matter… he’s willing to do a voluntary repossession, or file bankruptcy, he doesn’t have much to loose. He just wants to do the right thing. I figure if the bank did a repo, sued him for the balance owed and garnish his wages, they still wouldn’t collect as much money as if they had done a refinance with pre-arranged terms. I’m I wrong in this assumption? I was going to loan or give him a used car so he wouldn’t be without transportation. Thanks for any suggestions in advance.