What is the ruling regarding someone who dies a natural death but while abroad?

There is no difference between one who dies in his own country or in another country. What matters is the state in which a person died, not the place of his death. There is no harm for his family to offer the absentee prayer (Salat al-Gha'ib) for him. They may also transport him to their country for burial if he has not yet been buried, provided that his transport does not result in a delay that might cause the body to decompose, bearing in mind that delaying burial is contrary to the Sunnah.