Valiant is no more, Drunk Driver totaled it.

Although it is not a 63, here is a link to a REALLY nice 65. Hopefully, that will help with value comparison for like vehicle. Sorry for the loss of a family heirloom. :(
1965 PLYMOUTH VALIANT - cars & trucks - by owner - vehicle... (craigslist.org)
You just can not compare the 63 to this car. But really sorry for your lost. But I hope you get a fair price for it and you can purchase the car back from them to sell off parts and such.