Edwin, the Tlingit elder who oversees Cole's sentence on the island, isn't exactly someone to mess with. Although he's old, he knows how to survive much better than Cole does and refuses to take any nonsense from a disrespectful kid:
"Don't drown in self-pity," Edwin said. "You have more than most people. There's a whole box of your mom's letters waiting for you back in Drake. She knows you can't have mail, but she still writes every couple of days anyway." (24.28)
But despite his tough exterior, Edwin doesn't want to make Cole's life terrible. Far from it, in fact—he actually cares about Cole and wants him to succeed, showing Cole things he did when he was an angry young man who needed to change. Edwin guides Cole through rituals like soaking in the cold pond and carrying the ancestor rock in order to get more in touch with himself and the world around him.
In the end, Cole even remarks that Edwin has been more helpful to him than lots of the professionals that he's been to:
He turned to Edwin. "You know, the stuff you just told me makes more sense than all the weird things the counselors and psychologists have told me in school and at the detention center." (17.56)
Together, Edwin and Garvey really do form the perfect team to help Cole not only get back on track, but start down the path to a better, brighter life.