Both of the Kellers are heartbroken over their daughter Helen's disability and the way it cuts her off from communicating with others. However, the two have varying levels of optimism regarding her chances of being cured or at least of being able to communicate with them.
While he is normally a stern man with his family, Captain Keller tends to be lenient with Helen because of her disability. He feels she is to be pitied above all and allows her to essentially live as an animal because he thinks there is no other hope for her. Even when his wife Kate wants him to write to yet another doctor about Helen, he is reluctant and only believes it will break their hearts all over again. He is so despondent over Helen's situation that he believes they should just put her in an insane asylum, but Kate convinces him not to resort to such an extreme.
Softer and more openly compassionate, Kate Keller allows herself more hope for her daughter's future. While resistant to Annie Sullivan's tough love methods at first, she comes to respect her and turns Helen over to her complete care. Her willingness to trust Annie is what allows major change to come into her daughter's isolated world, allowing the young girl to communicate with others at long last.