How would you describe the child in Elizabeth Bishop's "Sestina"?

Elizabeth Bishop's poem "Sestina" has two characters: a grandmother and her grandson.

The child is a perceptive boy, because he can sense his grandmother's sadness even when she tries to hide it by making jokes. He has a very active imagination that can be seen in this drawings: he draws a man with "buttons like tears". He feels lonely and distanced from his grandmother and uses this imaginative drawing as a way to escape it.