Bought a car with Tax ID number 6 yrs ago, stopped making payments, can the bank track us down then?

My boyfriend and his father bought a car in 2003 they paid down $4,000 and the car was around $13,000... At the time neither one of them were legal in the US. They bought the car using their tax ID numbers, and their drivers licenses. The car title, registered, and insured under my boyfriend's name. And the car's lease was under his father's name. In 2007 his father stopped making payments, the bank called a few times asking to speak to his father. Since then the car has gone into a collection agency. I know they own then about $12,000 We have heard nothing from the bank since. My boyfriend now has a Greencard, so he has the car insured under his name. I know since the tile is in his name as well, he legally owns that car. And since theirs a lean they cannot transfer the car into the fathe