Can you write a summary of the theme of grief and sorrow?

When Mattie's mom dies, she asks Mattie to promise that she'll stay on the farm and help her dad. Mattie consents. But this means that Mattie cannot go to college, which is her personal dream. If she weren't consumed with grief after losing her mom, Mattie most likely would have the perspective to know that giving up on her dreams is not what her mother intended for her. This blindness as a result of grief also gets in the way of Mattie's relationships because the people around her who care about her can see that she's unhappy because she's holding herself duty-bound to this promise to stay on the farm.