Torvald Helmer is the uncompromising head of the household in A Doll's House. He is self-absorbed, self-satisfied, and rather oblivious to the inner lives of others.
We can see Helmer's lack of insight in several places in the play, most prominently in his understanding of Nora.
He is completely unaware that Nora is capable of making serious decisions and is baffled at the play's conclusion when she announces that she is leaving him.
Also, Helmer has no idea that Dr. Rank is seriously ill and going to die. He is surprised when Nora tells him this even after witnessing Rank's unusual behavior at the party.
Helmer seems to believe that his professional life and his own opinions are the only things he should be expected to consider. This is evidenced by his habit of advising Nora, by his rules for the home, and in his coversations about the bank and about proper behavior.
Of all the characters in A Doll's House, Helmer is the most innocent. This is, arguably, a result of his lack of empathy. His ignorance regarding the inner lives of others functions as a curtain between him and the world of experience.
He is surprised by Rank's illness and surprised by Nora's attitude and, beyond his surprise, he is unable to understand Nora's point of view regarding her need for personal growth and an identity of her own. Helmer lacks the experience and depth to understand.
Believing that his views define his household, Helmer has difficulty making the mental leap that would allow him to see things from Nora's point of view.