Need help to save my Father-in-laws car

Well, maybe think of this another way. If you sell the car, you will likely not get what it is worth. Some prick will always take advantage of you when you are down. So.......put the car on blocks. Drop the insurance. If it's not costing you anything, it ain't eatin.

Put yourself in the position to have to do what you would without the car. Don't even act like you own it. Seriously, how much do you think you will get? It's not like it will solve all of your financial problems. That money will be gone before you know it. You will have nothing to show for your memory.

Just trying to help you think outside the box. If it is that important to you, and it sounds like it is, maybe try something different. Sometimes the most obvious isn't the solution.
Think on it and pray on it.