This just happened to me. Can't get him to come back, and the game won't let me drive without Jackie in the car.
Tried F5+F9, didn't help.
Tried summoning the car again, didn't help.
Tried getting in a fight with NPCs, including cops, Jackie had zero reaction.
Time to reload a save, and report this bug. At least it's amusing, in a way.
Edit: I didn't need to reload, after all; I simply ran to Viktor's clinic instead of driving there.