Why does Cole become frustrated with Peter when he first comes to the island?

Cole seems to expect that Peter is going to settle in quickly and will accept the help Peter and Garvey are trying to give. He becomes frustrated very quickly and ask Garvey how long he's going to have to sleep in the tent while Peter sleeps in the cabin. Garvey counters with a question of his own. He asks Cole how long a person remains afraid after they've been beaten as badly as Peter was. Cole accepts that but his patience is quickly at an end again. The next time he's thinking along those lines, they are gathering firewood together. Peter refuses to help. Cole tells Garvey that he hopes Peter realizes they are gathering the firewood so that Peter can remain warm. Garvey counters, saying that Cole's actions are why they are all on the island together in the first place. Cole suggested that Peter come to the island and he swore he was ready to accept the responsibility for helping Peter begin to heal, but when it comes down to the actual work, Cole is still sometimes struggling to meet his obligations and to keep himself on track.