What does Jack think about as he prepares the cows for milking after realizing why Phoebe wanted him to say grace? How does he feel as these thoughts enter his mind?

Jack begins to think about his father and how resentful he is that Dale has gone. He imagines his father driving down the empty mountain roads alone and unburdened. He feels both hatred and envy that his father is free while Jack works so hard on the farm and sits with his family in church behaving as if everything is fine. These thoughts make him cry.