What should I do about my sister who works as a payroll accountant in a tobacco factory, knowing that this work is reprehensible, and she refuses to leave it, claiming she needs the money?

Smoking is forbidden (haram), and therefore it is not permissible to work in a job that supports it, such as your sister's job as an accountant in a tobacco factory, because it involves cooperation in sin. Thus, she should be advised to look for a permissible job, or to get married, or to be financially supported if she is in need and cannot find a lawful alternative. In such a case, it is permissible for her to work out of necessity, which is to be estimated according to its extent.