For the structural repair, it depends on how clean the break is and if there is enough glueable surface. If it's a long crack, it often just needs to be glued and clamped. If its a short break right across the grain, it may require splines or more.
Is the face of the headstock intact?
And then there's the question of the finish. Are you ok with seeing the crack? My Orville is repaired and you can see it/feel it, but it doesn't bother me. I believe Vs 64 is the same.
Gibsons have nitro finish, so new lacquer can be airbrushed on to the old and it blends in.
All that to say, it could be anywhere from $200 to $2000 depending on the severity and how you want it to look afterward.