Can tourists study in Italy without a student visa?

My cousins are filipinos from dubai (they live and go to school there) and they went to italy as tourists with there mom (they are all under 18). They told me that they have decided to continue their studies in Italy, the problem is they came to italy as tourists and they don't have a student visa, their mom decided to stay there too. What can they do? they don't want to go back to Dubai because of family issues. Can anybody please give me an answer... PLEASE