Oops i thought it was you
As far as i know you can still claim your pension even though you are no longer a Philippine Citizen.
I'm only basing this on my wife's oldest brother who is a Canadian citizen and no longer a Philippine Citizen. He is 65 and managed to have his pension payed directly into his account.
If he managed to do this i cant see why Arthur's wife wont be able too.
As with a lot of things here it can vary from case to case.