Hi guys
unfortunately my first post here is a cry for help.
It's actually my mates car but he is stranded so I'm doing the donkey/internet work

He was driving along and suddenly the engine lost power.
Now the car won't start and is sitting on the hard shoulder of the motorway.
The engine is spinning on the key, but doesn't sound like it's trying to start. My mate is worried that the chain has gone, but in my experience, broken belts/chains generally seize the engine as the valves hit the pistons etc. Is it possible for the M42 engine to lose it's chain and not damage anything

(I know some engines are non-interference).
I'm suspecting some sort of sensor failure. Maybe a TDC sensor or something.
Plan to get my tools and have a look after work, so any advice help would be appreciated.
Thanks in advance