A man asks someone to tell him about his mother, and the request sounds more like a demand. He says he has to "come to terms with her," and the short line "I must" shows how urgent this is. Nothing in the poem tells us who he is speaking to, or what happened to her, so we're left with the weight of the question rather than the story behind it.
The strongest moment comes in the mirror. Every time he shaves, he sees her life in his face and her ghost in his eyes. She isn't gone, because he carries her with him and meets her each morning. The last two lines are the most telling: he will hear anything, but he can't accept being told "there is no reason." That suggests something painful or unexplained in her life, or in his, and he needs it to mean something. The mood is raw, quiet, and a little desperate, like someone who is asking calmly but is close to breaking.