If he wrote it as part of his job, the university (e.g. if he wrote it for the class he is teaching): anything created while an employee is a work-made-for-hire and belongs to the employer. It would also belong to the school if he used school resources to create it (e.g. student help; school-funded research or school equiptment); the use of their resources gives them an interest in it.If he did not write it for the class he is teaching and did not use school resources, he would own the rights to since it would not be a work-made-for-hire (not all things made while employed belong to the employer: only those things which are part of the employee's job or which are created with employer resources), unless he had signed some written agreement with the school, which agreement, by its terms, gives them the copyright; such an agreement would be legal and enforceable.