This is perfectly legal for your father to do. The fact is that not all employees need be treated the same, or even fairly. The only time that different treatment would give rise to a legitimate claim is if constituted legally actionable discrimination (or retaliation). In other words, discrimination in the workplace is only illegal if it has to do with a person's race, religion, nationality, age, gender, sexulal orientation, or disability. Otherwise, it is perfectly permissable under the law.Note: Additionally, such treatment must not violate company policy, or the terms of an employment contract or union agreement.To be certain of his rights under specific state law, your father should consult directly with an attorney in your area for further advice.