The grandmother is the glue that holds the family together.  She is the matriarch and refuses to let the lawlessness and chaos of the political setting dissolve her family as it is ruptured the bonds of so many others.  The grandmother displays this in leading her family through Kruger Park and ensuring that they are nourished with whatever they can find in their voyage.  She also represents the matriarch with the establishment of the family's life in the refugee camp.  She works as a brick mover, while her grandchildren can get an education.  In this light, we can see how strong of a figure she is.  The grandmother is a vision of redemption for authority in a setting where authority is either subversive to individual attempts at collectivity or simply absent from these endeavors.