Hi Ash,
It might be worth checking it out with a K2 meter as a sort of preliminary investigation. Check around the house for EMF levels, making a note of areas that are giving off readings due to electronic circuitry and other devices etc (so that you can justify the validity of any activity you may get from the EMF meter as paranormal- also, constant very high levels of EMF from some household appliances can allegedly cause disturbed brain functioning, including hallucinations in extreme cases, so this can be something to consider). Finding out from your friend where the most active areas in the house are and then asking a few questions with the aim of getting a response from the K2 would at least give yourself and your friend an idea of the strength of the haunting, but you may not get any response at all, even in very haunted locations this happens. Maybe if you could get hold of a dictaphone or tape recorder you could run a few EVP session at the same time?
If it's not too far away then I would definitely suggest going over on a casual basis and testing the K2 out!
Regards,
Robb