I don't know, I think he should be concerned about it, I mean this thing is obviously disturbing his and his parents peace, now i've read some information and done reports on things like this, and apparently if his cupboards are opening and closing that means that this ghost or ghosts can grasp solid objects, which means he might, key word "might" have a poltergiest problem. Now the definition of a poltergiest is-
A ghost that manifests itself by noises, rappings, and the creation of disorder.
Also, what I found in my research are that poltergiest ghosts are the ones that actually can physically hurt people.
This is a question to Brian...has there ever been an instance of when the ghost seemed to be "after you" for a period of time, like were you walking under a shelf when something just fell off and almost hit you? If so, you need to take those steps that bring in the priest/father/holy person to rid the spirit. REMEMBER poltergiest ghosts are different than the regular "house hauntings" they are dangerous, especially if it was somebody who died in agony...
thanks for your time