Your unpaid car loan with Santander appears to be passed the Texas statute that limits a debt collectors ability to legitimately file a collection action in the courts to 4 years.
Because your debt with Santander is passed the SOL does not mean debt collectors do not file collections in the courts. They still do sometimes, and I will help you explore the likelihood of that happening. But if a debt collector does take this to court, your defense is simplified when the debt is time barred.
First, who is the attorney you received the collection notice from? Does that attorney have an in state address on their letter head?
Second, who is it that the attorney says they are collecting on behalf of?
Should you resolve your collection debt with Santander Bank.
What would be your motivation to settle the Santander debt? People have different reasons for resolving bills that went to collection. But if you have next to zero risk that the attorney collecting would file with the court, you will want to focus on the purpose of negotiating a settlement, and especially if the debt has been sold off to a debt buyer.
Settling now, even though it has been several years since your account went delinquent, could improve your credit in the eyes of different types of lenders. Are you thinking of getting a home loan or refinancing in between now and when the Santander collections account drops off your credit reports? Are there other reasons you would want to get this account to reflect a zero balance owed status on your credit. And who else besides Santander is showing this account on your credit (if anyone)?
If settling is not done for credit purposes, and not to eliminate the risk of being sued, then it would likely be a goal for personal reasons. Those are good reasons too.
If you are motivated to settle, you would typically connect with the collector on the account. You will often find you are in a better position to negotiate if they can no longer legitimately sue, and if you are not under pressure to accomplish anything with your credit (pending loan approval).
You mentioned you believe Santander sold the debt several times. Whoever holds the account now, if not the bank, will have paid a fraction of the balance to obtain the legal rights to collect. What was the settlement offer from the debt collector? If settlement is your goal, what is a target amount you are willing and able to pay, if less than the offer they started off with?
You can answer my questions in the comments section below and I will have more feedback. Anyone reading this page, who has questions or concerns about settling collection debts from Santander Bank, is welcome to post in the comments for feedback.