Lots of good suggestions here, but a lot of them seem to overlook that he's getting good spark from the lead out of the coil. So, there's nothing wrong with the points, condensor, grounding, voltage supply, etc.

The spark is not getting from the coil lead to the individual plugs. That means there's a problem with the rotor, cap, or (less likely) that the timing slipped enough to throw the phasing off -- the coil is firing when the rotor is between terminals on the cap.