The speaker of the poem is the parent of the son walking alone to school. The decision to refer to themselves in the third person is fueled by the fact that the poem narrates the actions of both parents. Sometimes it is the speaker, and sometimes it is the father, hence the vague "watcher's heart." But it also emphasizes the perceived distance between the parents and their son. As if to illustrate the way they are further receding into the background of their child's life.