What are the implications of the interactions between Walter and Beneatha, and what does their relationship contribute to the play?

Walter and Beneatha are siblings who have a complex relationship and hold different views regarding gender roles, education, and culture. Walter is older than Beneatha and does not initially support her dreams of becoming a female doctor. Walter continually antagonizes his sister for her unique views on gender issues as well as her affinity for African culture. Walter may feel intimidated or self-conscious because his sister is educated and attempting to fulfill her dreams while he works as a chauffeur. Despite their contention, there are times throughout the play when Walter and Beneatha get along and joke with each other. After Walter receives the money from Lena, his mood becomes lighter, and he jokes with Beneatha by acting like a native of Africa. Their ability to get along and act amiably illustrates what their lives would be like with financial freedom and opportunities to pursue their dreams.
Beneatha is younger than Walter and is annoyed by her brother's lack of support and understanding. She disagrees with his views regarding female roles in society, education, culture, and what to do with the insurance money. She criticizes her brother for his backward, traditional beliefs and ridicules him for losing the insurance money. She is unsympathetic towards Walter's unfortunate situation and resents him for losing the money. Despite Walter's mistake, he makes up for it by refusing to sell Lena's home back to the Clybourne Park community.
Overall, Walter and Beneatha's relationship contributes an interesting, exciting element to the play that creates tension and action in the Younger household. Their relationship also allows Hansberry to provide social commentary to the play by juxtaposing traditional versus modern perspectives.

Walter and Beneatha's relationship is one between siblings. The relationship between siblings can be simultaneously loving and contentious. There are moments in the play that reflect this. The two can be very playful with one another, as when they mimic their presumed African ancestors, and they can be resentful of one another.
Walter is about a generation older than his younger sister. He envies her opportunity to become a doctor—a feeling that he demonstrates with scorn. The play never makes it explicitly clear why Walter envies Beneatha and her collegiate friends. We do not know if he never excelled in school, if he met Ruth very young, or if there was an expectation that he go to work soon after his father's death (as he was the only remaining male in the family). However, there is the sense that Walter came along a little too soon, a little too old to engage in the race consciousness and Civil Rights movements. It is a state that leaves him feeling stuck: he has his sister's aspirations but his mother's fears.
The siblings' interactions are also impacted by gender. Often, Beneatha is discussed as a foil for her mother, Lena, who is older, religious, and patient in the face of oppression. However, it is also helpful to see her as a foil for Ruth. Beneatha is active, whereas Ruth is passive. Beneatha confronts and challenges her brother, while Ruth never does this.