Why did the big brother go to jail at the end of Feichi Life?

The business he was engaged in was illegal. In the movie "Flying Life", the reason why the eldest brother went to jail was because the business he was engaged in was illegal. In the film, Zhang Chi borrowed money from his eldest brother and sang a song for him. This song made him realize his mistake, so he took the initiative to admit his mistake and surrendered, and was eventually imprisoned. "Flying Life" is an inspirational comedy film produced by Shanghai Tingdong Film Co., Ltd., directed and written by Han Han, starring Shen Teng, Huang Jingyu, Yin Zheng, Yin Fang and others. On February 5, 2019, the film was released in mainland China. The film's box office exceeded 1 billion in six days of release. The film tells the story of racing driver Zhang Chi, who was banned from racing for five years and had his driver's license revoked for illegal drag racing. However, he never forgot his love for racing. In order to regain his former dignity and honor, he decided to return to the racing world to A rough story of perseverance and renewed success. In September 2019, the film won the Best Cinematography Award at the 17th Pyongyang International Film Festival.