The narrator's father canno see. He is blind, but he supports the family by being a preacher and professional piano tuning master.
The narrator never felt shy or embarrassed about his father's condition. One time when he was still in the elementary school, he asked the teacher to invite his father to give a speech. His young classmates out of curiosity asked many questions about blind people. Therefore the sentence. It was a special experience for the narrator.
kusualapv: let me take. I think this is patient focus because the subject of the sentence is the semantic object dengec so literally similar to taken by me