He doesn't do anything. Aticus is a very patient character
At one point in the book, Bob Ewell spits in Atticus's face for humiliating him in court.
Bob Ewell spits in Atticus's face outside the post office as a way to express his anger and hostility towards Atticus for defending Tom Robinson in court. This action showcases Bob's bitterness and lack of respect for Atticus and his beliefs.
Atticus remains calm and composed when confronted by Bob Ewell's threat. He does not escalate the situation and responds with dignity and respect, showing his unwavering commitment to justice and fairness.
He harassed her by following her to work everyday. The Ewell's also whispered obscenities at her and only stopping when Deas (Robinson's boss) threatened to get him arrested.
Link Deas threatens to have Bob Ewell arrested for harassing and intimidating Helen Robinson if he doesn't stop his behavior. Link warns Bob that he will not tolerate any mistreatment towards Helen.
Bob Ewell spits in Atticus' face out of spite and a desire for revenge, as he is angry that Atticus was able to prove his daughter Mayella was lying about the assault. Ewell's pride is wounded, and he seeks to humiliate Atticus as a form of retaliation.
Although he won the court case, Atticus obviously proved Tom innocent, and he completely sided with Tom anyways. Bob Ewell is angry that Atticus sided with Tom, and he tries to take revenge by killing Atticus's children, scout and jem. He does not succeed, thankfully!
Atticus believed that Bob Ewell's desire for revenge was motivated by his wounded pride and need to exert power over others. He thought that Ewell wanted to maintain his ill-gotten sense of superiority by targeting those who threatened that image, such as Atticus and his family.
Bob Ewell confronts and threatens Atticus for humiliating him in court during the trial. He vows revenge on Atticus and his children, Scout and Jem. Atticus remains calm and uncompromising in the face of Bob's aggression.
Bob Ewell threatens Atticus Finch after losing the court trial by spitting in his face and vowing revenge. He also tries to harm Atticus' children, Jem and Scout, to get back at him.
Mayella Ewell.
Even though he (Bob) won the verdict, he knows that he as really close to losing. The only reason he won is because the convict (Tom Robinson) was black. Bob knows that if Tom wasn't black that Bob would have been convicted right away.