If I asked you to pray for me, would you do it??
Well, as Catholics, we believe that a) it's not only the living who can pray for us but also those who've gone before us in faith and b) the prayers of those who themselves led holy lives are particularly powerful in the sight of God.
That's all there is to it, really.
Nothing wrong with that is there?
The story explicitly says the nun prayed to John Paul II.
Well put. I love it how Protestants say we are going to hell for praying to someone "other than Christ," and then turn right around and say "Please pray for my mother, she's got cancer." We don't just ask those who are with us now, we ask those who obviously got it right - saints - in addition.
It says she was healed after praying "to" the deceased pope not after asking him to pray for her.