Upaid vehicle property taxes (Virginia)

A relative in Virginia is suffering from significant mental health issues and has a vehicle that has been sitting unused on private property for several years. They have not paid the personal property taxes, and the debt has now gone to a collection agency. Because of their condition, they are not realistically able to help pay the debt or arrange to sell or transfer the vehicle. Also credit-score consequences are not a significant concern.

Another relative who they are living with is thinking of paying the debt. I’m trying to think through whether this is a good/useful thing to do. The current debt is around $1000. The car has not been driven for 3+ years, has flat tires, not sure if engine would start. Don’t know the make/model but guessing a value of $5K to $10K.

What happens if the debt is simply ignored? Will the unpaid debt prevent the sale? Ant way to surrender or abandon the vehicle to stop future tax liability, particularly if the owner is unable or unwilling to participate? I’m doubtful that we can find a title.