Someone I know has a job that requires him to be on call 24/7 and work 40 hours Monday through Friday. He recently asked for a vacation that isn't until November. The vacation he requested would be 10 work days which they've approved of. Now they are denying his vacation request because they are now including the two weekends that he will be gone as work days even though he does not work those days. Are there any laws or regulations that can prevent them from doing this to him?