Along with what others have said, I think I would give Gruhn Guitars in Nashville or Elderly Intstuments in Lansing, MI a call. They may be able to give you a proper appraisal and you may even want to consider consigning to either of these stores. Both really know their stuff and will take very good care of your banjo for you. An instrument this special and of this value, I believe would be worth taking these steps.
I would also, as Banjoe mentioned, give Ben a try… send him a message.
I looked on Reverb (a well respected site that anyone can sell musical instruments and gear) and there was only one like yours… an 80’s model for over 5300.00.
Right now is a great time to sell as all the builders are way, way behind because of covid and folks are spending their stimulus $$$!
Good luck and sorry to hear of your loss.