First of all, from the beginning of the film, it shows that Jack is not good at life skills. He belongs to people who enjoy life. When his car broke down, he didn't know what to do. He can only kick it out and probably doesn't know how to maintain it at ordinary times. Finally, Ennis helped him fix it.
After the movie, Jack has been driving a long way to see Ennis. He also mentioned that it is very likely that he often goes back to his hometown, so it is very likely that there will be an accident with the car tire.
abstract
Adolescent boy Jack, his 5-year-old half-brother Manuel and their mother Sana live together in a high-rise apartment in Berlin. Judging from their clothes and decorations in the house, this single-parent family is not poor. Mother Sana obviously loves her two children, but she is also very selfish and irresponsible. She often leaves her children behind and hangs out with friends and boyfriends.
So little Jack became the head of the family. He must take his younger brother home by subway, wash clothes, and then make breakfast for them with any food left in the room. In the middle of the night, Jack will even interrupt his mother who is having sex with a strange man and ask her to cook dinner for herself, while Sana will cook for her son naked. Neither side is surprised.