Jack notes that his dad — who also struggled with alcohol addiction — was 63 when he had him, so it's assumed that Bobby, his older half-brother, is at least 30 years older than him. Jack treats his brother, who works for him, poorly, and there is constant tension between the pair. (Bobby had a go at being a rock star when Jackson was a kid, but then has to care for him after their dad passed when Jack was 13, so there's definitely some jealousy and animosity.) Although Bobby is clearly concerned about the path his brother is on and it's obvious that Jack loves Bobby, rather that talk through their issues together, they often fight, and Jack at one point turns to violence and punches Bobby in the face. (To note: Ally also punches someone in the face at one point.)
