E side of the pond = Europe? How does a passenger (for that's what the other pilot is legally) need a type rating?
The point is, if the second pilot has a type rating, he
may use the radios or touch controls, as long as the Ops manual caters for this for a public transport flight. If not, he
cannot do either because yes, he is classed as a passenger.
Which is why I said the type rating matters.