Open Question: What if I file for bankrupt?

I have a vehicle that I co-signed on for a cousin, its been 6 years since and and i am in all kinds of problems because of it. I don't want to pay for a vehicle that got reprocessed and that i never even drove. Cousin is now filing for bankruptcy and i am stuck with that bad debt of $12,000.00 plus my own debt of 9,000.00 is credit card debt. Please any advice on terms and conditions for bankruptcy.