If the holder of the student pilot licence was in fact just a passenger on the flight, the fact that s/he was a student pilot licence holder is completely irrelevant and the currency or otherwise of his/her medical certificate is completely irrelevant, unless there was some causal connection with the accident. Indeed, it would be completely irrelevant if the PICs medical certificate was not current, unless there was come causal connection between a medical condition suffered by the pilot and the accident.