Why does nnaemeka think that his father okeke will be unhappy when he hears of nnaemekas engagement

In Chinua Achebe's Marriage is a Private Affair, Nnaemeka wanted to inform his father about his engagement with Nene but he was bound to tell him as he knew his father would be upset on this sensitive issue. When Nene suggests him to inform his father through a letter, Nnaemeka describes that to his father it's not "happy news" because this marriage was not arranged by his family. A marriage is arranged by the families according to the Ibo tribe. In addition, when the marriage is arranged it is made assured that the two speak the same tongue or come from the same tribe. To this he says:

"It would not be wise to break the news to him by writing. a letter will bring it upon him with a shock. I'm quite sure about that."

in the quotation from passage, connie willis states that literature is a way for authors from the past to communicate with readers of today. we can read their stories, books, and other texts to learn lessons about life. willis refers to these lessons as messages “from beyond the grave.” willis has a favorable viewpoint about the timelessness of literature.