In "Sometimes a Dream Needs a Push," why does the narrator's dad always seem so quiet?

The narrator's father seems to have taken the crash hard. As his mother tells him, his father seems to blame himself for what happened. However, the disconnect between the two seems deeper. The narrator notes in the opening paragraph that his father had hoped he would follow in his footsteps, becoming a basketball player as well. The father seems to feel the accident disappointed those dreams. In general, it seems like the father does not quite understand his son, that the wheelchair creates a distance between them.