Rasheed strikes me as the weakest character in A Thousand Splendid Suns.
Hosseini defines strength in the ability for a human being to grow from a weed or, harami, into a flower. The setting of Afghanistan is one where both the land and the people have been "ripped out and tossed aside." Hosseini suggests that when human beings can transcend such a reality and become something more, strength is evident.
Rasheed remains as a weed. He is incapable of growing into anything more than he is. Rasheed is a bully and he remains as such. He does not grow and is unwilling to change. He lacks the courage to embrace change. Nowhere is this better seen than in his attitudes and actions towards women. He believes in controlling Lalia and Mariam. Through degradation and violence, Rasheed shows his cowardice. He continually makes reference to the social and legal system as supporting his actions. This reflects his inability to look critically at his own actions and assess his own attitudes, showcasing his emotionally frail nature. Rasheed needs Zalmai to follow his lead as a way to confirm that what he does and believe is right. In these ways, Rasheed shows that he cannot comprehend the reality of women as equals. He is a scared man whose lack of growth is representative of his weakness.