What is the ruling on a girl marrying when her brother refuses to let her marry because he harasses her, and she runs away from him to marry the young man she wants?

If the brother's harassment of his sister and his prevention of her marriage are true, then this is contrary to Sharia and human nature. He must be advised and warned. If he does not desist, he should be threatened with reporting him to the authorities. The sister should treat him like a stranger; she should not allow him to be alone with her, nor should she reveal her adornment in front of him. Her escape is permissible if it is a deliverance from his evil or a means for her to get married, and her other brother should marry her off. She is not allowed to marry without the permission of her guardian (wali), and if the guardian refuses, she should refer the matter to the Sharia judge.