Visa types for Student in China about 18 years of age- mother has work permit

Hi, I have work permit and my son was living with me in china on dependent S1 type. But now he is 18 years above, and i learnt that he cannot get depended S1. The school is not in position to help the documents needed for study X type. Request you to help me with possible options which can help him to get one year stay in China with me. He has residence permit as of now.