As a former child of manipulation, I know what your kid is going through. He is very confused and will give into ANYONE who gives him the slightest bit of positive attention, even if that means putting your relationship with him at risk, which is what your ex SIL is doing. People like that don't care; they think it's a funny game and it's so vindictive and evil to use the children like that.
Every time my grandmother would get mad at my mom, she used us to get information and use that against my mom and reward us for our bad behavior to try and detatch more and more from our mother. It was SICK what she did, and she's still trying to do it with my brother! You need to distance your child and his aunt, period.
You also need to inform your ex SIL how sick she is by doing this. Kids don't understand the concept of truth vs. made up tales, so he may be telling his aunt lies about you, but it's not his fault. She's the one who is WRONG here, and she needs to be put in her place.
Your child is angry and confused, because here's his aunt pitting him against you, but deep down, he still knows who his mother is. In his mind, it's this: "Why is mama so bad? Why is Aunty so good?
Who do I trust? Aunty says mama doesn't like me, but she still takes care of me?" He's VERY ANGRY because of the confusion and the manipulation, and you need to cut off all communication with her.
As I grew up, I ended up cutting off all contact with my grandmother, my father, and my mother for a good 4 years because I was just so hurt and confused at who to trust and what to believe and it took me that long to assess everything and take it in and learn what was really going on growing up. Since then, I have maintained contact with my mother and father, and have pretty much steared clear of my grandma and her evil ways. Your child is still young enough to come back to you without this having to happen.
Good luck :).
You need to get the child into counseling to undo the damage already done and understand that this is a common problem...in his six year old mind he thinks if BF is gone Daddy will come back...he needs to really understand that adult relationships do NOT always work and if Daddy and Mommy decide they can not be a couple anymore, then nothing anyone does can make them a couple again. The best person to do this a counselor with experiance in children of divorce/broken relationships. I would also look into getting family court to order SIL stay away from the boy...she is deliberating interfering with the Mother/Child relation ship and here in the USA parental interferance is not tolerated by Family Court...look into that and good luck.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.