Okay, my head is starting to hurt. I've done all the reading of your Code of Virginia, Title 18.2-308 that I can stand for now.
Basically, if you have any intention of returning or otherwise availing the firearms to your son within ten years of his conviction (in ANY State), you are guilty of 18.2-308.2:1, a Class 6 Felony.
As the unwilling participant in a felony, it would behoove you to immediately surrender the arms to your local P.D., contact the County D.A., or consult an Attorney. I found nothing as to the legality of your son "owning" while not "possessing" firearms, so I won't speculate as to the outcome of such a claim, if made by him.
Unless they are something special to you, it would probably be best to rid yourself of them in some way. Which way you choose would be where the educated/experienced opinion of the aforementioned parties will serve you best.
Sorry for your predicament, and I wish you the best of luck!