@sadiebelles I'm sorry to hear that OP. How old are they now?
I guess some people are more predisposed to certain traits than others. Both positive and negative traits.
My older brother used to lie and be very sneaky as a kid. He had a really cunning streak in him and was a compulsive liar. It was bizarre if anything because no one else in the family is like that.
I remember my mother trying absolutely everything. She gave him positive male role models. Always praised him when he told the truth. Tried ignoring all lies. Tried confronting all lies. Every parenting method there was. This was from around aged 5 I think my mum said. Before I was even born.
He became more and more sneaky as a teenager and did some dreadful and spiteful things which do not align at all with anyone else in the family (taking my mum's valuables to the pawn shop once despite having ample pocket money and resources).
Anyways, when he got to his twenties he appeared to have grown out of it and all was well. My mum said she must've finally matured and grown out of it.
That was until we'd recently found out that he's been cheating on his wife for years. He's now in his late thirties. It appears has things have come out that over the course of his twenties and thirties he's continued his lying and sneaky ways both in work and his personal life. The man even has a fake name and job he uses in one of his double lives. In some lies he's an only child, in other lies he has 6 or 7 siblings that depends on him financially for support. He even framed a co worker for theft who lost their job as a result. You could do a netflix documentary about him, you really could!
Anyways. I've no idea why he does it. But when it all came out my mum thought back to him showing the same character traits as a small child. At aged 7 he once destroyed a class project but framed another child who was adamant it was my brother. All the teachers believed my brother as he was so believable plus evidence pointed to the other kid. So he blamed the other kid who got into deep trouble with both the school and his parents who were called in. My mum said she had a gut feeling it was my brother and the other kid had been framed. She felt bad for thinking it was him after he was so distraught for being blamed. Plus he was only 7 and what 7 year old could concoct a framing situation so efficiently with evidence and everything? My mum would've looked like a lunatic and really nasty blaming him.
Years later he was laughing about childhood memories and told my mum 'i remember when I was that kid got in massive shit for ruining the class project. Can't lie, it was me. But my god was it funny'
Absolutely chilling.