He is wrong: state and federal law has nothing directly to say about PTO and vacation policy (though it does have something to say about retirement benefits and health insurance) and each employee could have his/her own, unique set of PTO and vacation rules, number of days off, etc. In particular, there is no limitation on giving more vacation or other PTO to staff with more seniority or experience, even if they are direct reports of the same person that entry level staff report to. Certainly, employees cannot be treated differently in terms of PTO due to age over 40, disability, race, religion, sex, etc.--but so long as there is no illegal discrimination of that type, against employees due to specifically protected classes (of which race, religion, age over 40, sex, and disability are the main ones) different employees can get different amounts of vacation or other PTO.