What was the gift that the boy received from his father, and what does the gift say a out their relationship as well as the relationship the man had with his mother?

The narrator receives a gorgeous new piano as a gift from his father, illustrating the fact that a "big" gift represents having received few from him. The narrator then shares with his mother his growing desire to visit the South, after which, he learns that the reason he and his mother moved north is that his father was about to marry a white woman from a prosperous Southern family. However, he promised to take care of his son from afar. The narrator notes how much his mother loves and defends his father in their conversations, even though he has chosen not to build a life with her.