Why does Miig tell more of his story just to Franchie, rather than to the whole group in chapter 6?

I think that Miig notices that Frenchie is struggling to define himself both culturally and as a young man. Miig wants to help him better navigate his world. Miig believes that people are motivated by outside forces, and he says that the Native Americans who are running for their lives and the non-Native Americans who are chasing them are all intent on survival.