the 4 pin ECU (that ran at one time) has been switched out to another 4 pinner right? I'd disconnect the hot lead to the "point" of the ECU pentastar connector and disconnect ALL leads off of the coil primary terminals then jump 12V to the coil positive primary and to the "point" of the ECU pentastar connector and reconnect the 1 wire (that you just took off) from the coil negative primary to the appropriate ECU pin then crank it with or without the key. It must start! Oh dont forget to check the reluctor gap and a quick visual for any damage (teeth etc)while you have the rotor out adjusting the gap. yes he could try another battery or jump from another one with cables just like a regular jump start and if his batt has a bad cell it could be dropping voltage fast when cranking but I am a k.i.s.s. guy but we are running out of ideas & sometimes off the wall stuff does happen (part of Murphy's law) and yes I agree the voltage is going to go way up when the starter is disengaged.