Miraje...i am really sorry about your youngest. 11 is a hard age for all that to go down. My son was always a handful, but hes doing great now. I wonder if he was a handful because he sensed that pre BD dynamic and maybe did not know exactly what was going on. I hope your son gets the help he needs. He is still young and can make great turn arounds.
Regarding mlc and narcissist. I know we cant diagnose. But im under the belief that if it walks like a duck, and quacks like a duck chances are its a duck. Regardless of the title we give, Their behaviors are abusive, demoralizing, and overall bad for the soul. Cheating is abuse.
Now they were not always like this. But my theory, is that its because life was easy for them. Once the going gets tough, cancer, job loss, kids, sick parents... they look for excuses to jet out of there. They cant accept that they are acting like irreaponsible Pos, so the gaslighting and villifying amd rewriting of history starts. Thats a form of narcissim. They cant accept that they just cant handle life so they campaign against their family. Thats selfish. But its also manipulative. And theres a scary state of irresponsibility and denial.
Most of us qould have been able to accept this all easier if theybhad just been honest and said "i am selfish. I cant handle family life. I need out to live my dream" bit thats not what happened. And that why we are all on here trying to make sense and teying to heal.