Human Rights across National Borders

In Pakistan are visible thousands of children living alone in the streets, used by different kind of people for underground proposes. Then one finds them older entering Greece borders, bringing with them the underground exploitative activities as well as the solidarity support of local population living where migrant pass. Looking to the youngsters migrant flow from Afghanistan to Europe, is it possible to understand it when sociologist look at it as a problem of national stock and flow? Or does sociology need to adopt without borders methodologies