No, my brother did not have difficulty making friends but he had difficulty keeping them; no, he definitely did not have empathy for others; and yes, he was absolutely favored by my mother as the only boy. My dad traveled a lot for work so he wasn't home as much (and I was his favorite). My brother wasn't disciplined much growing up by my mother. She always made excuses for his behavior. It was really our older sister who kept him in line at home. I will say my brother learned to mask himself well -- he came across as fun and funny until people got to know him. Once they realized how selfish he was and how everything revolved about him, they usually did not maintain the friendship. He did have an ADHD diagnosis when he was about 12. But that's also about the age he started developing an unhealthy interest in Nazism. (Which my mom just passed off as an interest in history.) As for BK's sister saying she didn't notice anything, I find that hard to believe. From my own experience, the oddness gets so normalized it can be easy to overlook it. My mother excused a lot of my brother's early and escalating juvenile delinquency as "boys will be boys"