Only certain professions have a cap on just how many hours a worker can legally be scheduled to work (e.g. certain medical professionals, airline pilots and the like). Otherwise, unless there is protection via the terms of an employment contract, a union/collective bargaining agreement or even company policy, an employee can be scheduled to work 7 days a week. Also, an employee's treatment cannot be due to any form of actionable discrimination or retaliation, however that does not appear to be the case here.The fact is that most employment relationships are "at will", which means that an employer can set the conditions of employment much as it sees fit. For their part an employee can either quit, comply with their employers terms, or refuse to comply and risk termination. While seemingly unfair, it is the law.To be certain of his rights, your nephew can contact his state's department of labor or consult directly with an employment law attorney.