The DIS module is not a simple device. It is a complex electronic component and most of the issues it has are related to temperature. So just because the DIS is malfunctioning doesn't mean it won't be giving it the old college dry to keep things going.
If you disconnect the CAM sensor, you cause the engine computer to have to guess when the #1 cylinder is ready to burn some fuel. The computer will pick a coil to fire and fire that puppy. If the motor doesn't start, key off, key back on, and the EEC will try a different coil.
Once it runs, not having a CAM sensor shouldn't really affect things. As the EEC will just work off the crank sensor. (The engine will not run without a valid crank sensor input)
If the wiring is bad you don't necessarily eliminate it by disconnecting the sensor. A ground loop, or some issue that causes an intermittent signal from the sensor won't show up with the sensor disconnected. If the computer gets a flaky signal, it may work with it. If the computer gets no signal, it ignores that input.
If you have a buddy with an SC close buy, just see if you can swap DIS modules and see if the problem goes away. If it does, it's the DIS.