simply beggars the imagination.
This because you have you blinders on. Chartering isn't something that's done in US part 121 flying. There are plan B and C, such as a later flight and delaying the departure the DH crew was to fly, if there is another crew at SDF already, alter their schedule, this being unlikely at SDF for a number of reasons. There isn't an established process to call some charter service and find out if there's a king aire hanging around doing nothing. Aircraft of that level are expensive and tasked pretty heavily to afford them, not a guarantee ones available.