Shamus
I have dealt with many abuse survivors over the years.
Some lie and some do everything in their power not to lie.
As said before lying can be a way to get attention or a way to hide the truth.
It does sound as if your friend was in crisis mode and definitely in need of professional help. You needed to take care of yourself. People in crisis who are not getting the help they need can easily overwhelm those around them. You do a person in this situation no service to hang in there and buy into the lies. Eventually he knew he would be caught and find a way to leave - which is what he did.
BTW I come from a family of compulsive liars. I hate people who lie. Your story of your friend lying about his mother reminds me that one of my brothers told his boss our mother had died. When no one could contact my brother my mom whent to his work to ask about him and the boss told her he had taken a few days off because his mother died. And my mother's always tactful response was: "No I'm not. I'm right here." Needless to say he lost his job. This was pretty typical of him and he was always caught.
Another of my brothers was a really good liar - still is and still thinks he can get away with it. And he does for a while - he is pretty good. And the third brother would make you wonder but usually we could tell when he was lying.
My sister and mother don't even know what the truth is anymore. They have lied to cover the lies so much they don't know what they said.
And I always wondered why people would fall for my father's lies. But then I knew all the facts and they only knew what he told them.
No wonder I have a hard time trusting people. I would rather be silent than tell a lie. As a defense against liars I have developed a pretty good BS detector.
Now I'll tell you that everyone in my family has been sexually abused including both parents. Do they lie because they were sexually abused? Perhaps. But there was also so many other problems in the family. Maybe they lie because they were taught to. It might be a part of it but then it just might be a learned behavior.
And let's face it many JWs, especially those who get into leading the double life, become pretty good self-liars.