Thank you for your question. I look forward to working with you to provide you the information you are seeking.
Unfortunately, Nevada is a community property state. If you give back the car, your mom's estate would be primarily liable to the lender for any deficiency balance on the loan (difference between what they sell it for and loan balance) and your dad as her spouse would also be jointly liable with the estate for any deficiency. Thus, your dad could be liable for repayment of that balance if there are insufficient funds in your mom's estate to make the payment.
An alternative is selling the car yourself to get the most you can for it to pay it off or minimize the deficiency balance.
Another alternative, which I mention last because I presume that you could not qualify for the loan before which is why it is in only your mom's name, is you can seek to go to another lender and get a loan to pay this original lender off and continue to keep the car.
Legally, these are your alternatives.
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