1991 740 NA Rex/Regina 175K

Single digit temperatures. Car was left idling for 20+ minutes. When he came back to the car it had stalled. On the first attempt to restart it responded with a chugging engine for a short period of time and would not respond to throttle application. Additional attempts to start it resulted in engine turning but not firing. Three or four seconds of starting fluid into an open throttle body followed by hose replacement did not produce any evidence of wanting to run. Apparently he has no spark. He did not have the opportunity to check to see if the cam was turning before his ride home showed up.

I am sending him a coil assembly today in case the fault lies there. I do know that the coil assembly currently on the car was taken apart and the contacts cleaned as routine maintenance three years ago. If after plugging in the replacement it still fails to start these are the things I am suggesting:

1. Checking for spark at the plug wires.
2. Checking for spark out of the coil wire.
3. Checking for voltage at the coil.
4. Inspecting the crank position sensor cable for deterioration, although this was replaced around three years ago. I will have him gently wiggle the cable while cranking.

What else should he check or chase as a solution to this no start?

Thank you,
Randy