Can an employer really legally make you work 60 hours per week if your salaried?

I know of someone who has been told by their employer in New York state that he and everyone else that is salaried are going to have to start working 60 hour work weeks. He says he has checked into it and found that it's perfectly legal for the employer to do this. Obviously no one is happy about it but they plan to do it in order to keep their jobs. These people have families that need their time! How could this possibly be legal? How can they get out of being blackmailed to do this?