66 imperial crown – barn fresh what’s it worth?

I'm a veterinarian and was out on a farm call to look at some cows when I noticed a client had a old imperial on the corner of his property. It was his mother inlaws and was under the hay barn until 3 months ago when he moved it into the elements. The car has 45000 original miles and has had one repaint. Body is straight and has all the trim. Engine bay is covered in rats beats and he says he hasn't driven it under its own power in 10yrs. He is looking to sell it and doesn't know what it's worth. What do you guys think?

I will upload some photos and a pic of the fender tag this evening.