My sister recently told me that the Holy Father stated that he doubted the existence of purgatory. I frequently listen to Catholic radio and occassionally watch EWTN, and I’ve heard nothing about this. I assume this is false. Can you clarify?
Your sister has the obligation to document her claims. Ask her to do so. In the meantime, I recommend that you read Pope Benedict XVI’s encyclical Spe Salvi. He discusses purgatory in paragraphs 44-48.