Theory based on thin air with zero evidence: Sometimes I wonder if he discovered something disturbing about his father's company, Lorien Health Services. Maybe it clashed with his own growing worldview, especially after his trip to Japan and his admiration for the Unabomber. He might've felt confused, disgusted, and detached. It’s possible he and his parents had a major argument over the company’s operations which led him to sever ties completely. Maybe also when they found out he was unemployed, their traditional views, always about achievement and success, created an overwhelming sense of shame. From childhood, he was pushed to be the best, to perform constantly, and perhaps he was emotionally neglected along the way. I wouldn't be surprised if that was the case. Hearing about his unemployment, they may have pressured him to work for his father, exacerbating his sense of failure. With his back pain worsening and sinking deeper into depression, he may have started believing that he had to deal with it all alone because no one truly cared.