Do you remember when your son was 11? That's not a teenager..and that's when he was brainwashed.
Yes, I understand that Hildy. However, I have had experience with my own teenager and also we had my teenage niece come live with us for a year. What they believe as kids is often thrown out as teens and that's part of my difficulty. It is not that it happens just exactly why. Kids today are much savvier than I was when I was age 11. I could see my age group being brainwashed at that age far easier than today's children. Obviously by this case it has happened. I also understand the Patty Hearst syndrome where the kidnapped person eventually identifies with their abductor. It's just one of those areas of human psychology that I struggle with understanding.
It also probably helped that he has a stepfather, rather than a biological father at home...
People age 11 are able to think for themselves and are already embarked on their main life path.