Udaan climax

At the end of the movie the oldest son sees that his dad is going to marry another woman with a daughter so he thinks his dad is going to put his anger on another family. So he decides to walk out the front door and never come back his dad tries to stop him but he punches him in the face and ran as fast as he could. He went to his uncle and told him everything the next morning he went to pick up his half brother who was waiting outside for his first day of bording school. He also left a note and his dads watch and wrote down that he is taking his little brother with him and if he tries to call the police he'll tell them that he abused both of them and they walked away and never to look back.