Non binary is an end point in itself. 'Trans' is an umbrella term that covers MTF, FTM and people of either sex claiming to be non binary, or 'neither male nor female'. It's very difficult to define because every adherent of Genderism will use divergent terminology, but in plain language, that's what it is.
So this person is not going to become a man. They simply feel that they are not a woman because of some fairly hair raising sexist assumptions about what being a woman entails. This is nothing to celebrate, really.