Help w/ essay body aragraphs

The assignment is to explain the historical context or setting of Mulatto in regards to why the main character of this drama was at the mercy of societal forces.
Here is what I have so far, but Ineed help elaborating in the second paragraph.

The story Mulatto by Langston Hughes takes place in the south during the Great depression. Robert Lewis is the son of a white plantation owner, Colonel Norwood and a black house keeper, Cora. As an interracial man living in the Georgia during the 1930’s, Bert is subjected to segregation, discrimination, and harsh recrimination. These factors inevitably lead Robert to his death at the end of the story.
During the 1930’s all southern states had some kind of Jim Crow law’s. These laws prevented blacks and whites from using the same facilities.
Being a ‘mulatto’ causes Bert to be frowned upon by those who are white and black. He is expected to live as a black man would, go through the back door to enter the house, speak a certain dialect, and follow the orders of the white man. The Colonel paid for his mixed children to go to school, so that they would have a better chance in their endeavors. When Robert returns from school, his mother and brother pester him about not using the typical southern black vernacular.
In addition to the Jim Crow laws, there were certain unwritten laws that blacks were expected to uphold. A violation to these laws could lead to the person being lynched, burned alive, or some kind of brutal punishment. Robert makes his first mistake when he talks back to the white woman at the post office. A black man talking back to a white woman was absolutely unacceptable. The second mistake he made was when he drove past Fred Higgins, a friend of Colonel Norwood’s, and almost ran him off of the road. All of these would be acceptable things to do, but because Robert is half black and half white, he is considered to be rebelling.