the spark could be in the wrong phase
what like igniton leads on wrong as due to it being a wasted spark theres too many sparks there anyway
so lets recap, if hes done all the easy tests the he will beable to diagnose the hard stuff
chasing the loom should be the last thing on the list after sesting all the sensors and general parts first
oh and dont say cam timing as even when thats out it usually starts inless its sooo far out then in that case its obvious
now back to the point if all the simple stuf is checked ya need to get another car to compare em on mate