Well, it would depend on how big they are! And how many of them there are! Really, we can't really say what we would say until we are in the situation. It depends on the person; how open they are. Sometimes it is a time to develop equanimity and reflect that they are the owner of their own Kamma, and at other times we may encourage them to go to Asia and see how fortunate they are; which they probably would not like to hear. It really depends on how open a person is as to whether we spend our time giving them advice such as encouraging them to think about how fortunate they are.
In the famous story of Kisagotami, the Buddha did not actually confront her grief straight on -- he did not tell a women who had just lost her child and was in grief, that everybody dies. He rather asked her to go to the village and get a mustard seed from any place where no one has died.
Sometimes we can think of stories that may be appropriate, but it really depends on the person who is complaining, as to whether we can bring them out of the unwholesome and establish them in the wholesome.