In the story Cathedral by Raymond Carver towards the end of the story the blind man asks the narrator to describe the cathedral

In the story Cathedral by Raymond Carver towards the end of the story the blind man asks the narrator to describe the cathedral. Why is the narrator able to do so? whta does the inability reveal about him? why does the blind man tell the narrator to close his eyes while he is drawing? what does he hope to teach him? what is the narrator able to see with his eyes shut that he can not see with them open? Do you agree the narrator becomes more open? if so which are the words he chooses to reflect this increasing openness?