Hello Kiora Thank you so much for getting back on here and letting us know a bit more, although you still didn't say how it actually got resolved?
I did look into 'Stockholm syndrome' and yes this is def my D, even though her husband is the same age. How nice that you got a new baby GC during this horrid time, it must have been a God send. That's what I'm waiting for from my ND. She has gone away for the w/e, I really hate it when she is away as it makes me feel so alone (I don't let her know this). She txt me and said "you could foster + adopt a little girl" I replied " no Sarah, I need some flesh + blood GC) she replied "You will prob get some soon. Have you got a house made of sweets?" me; "no, but I can make one if it helps, promise not to put them in the oven ;-)) Lol
Yes Smileless my s.i.l is a 'narcissistic paranoid schizophrenic' (due to his drug taking of the last 11yrs!), I've studied this for the last year, and as you say; he pulls in allies and turns the situation around to make him the victim, even though it has all come from him!! That's terrible that your d.i.l's parents didn't go to their wedding, reading your story above, I think your d.i.l and my s.i.l have the same affliction, he does the same thing, turning stories around and is a pathological liar, which goes hand in hand with narcissism.
I, like you Smileless, am finding it easier in some ways (its less raw) but then worst in others, as its now been such a long time since I've seen them and no one in the family will talk about it, it's just become the norm and taboo subject! I have gone from really missing my D (she's my baby) and then feeling I hate her for what's she has done to me and her sister and to Laila and Jack, I am Laila's only real Grndparent, the others are 'step', so I'm sure Laila wont be too pleased, when she's older and learns that her real, devoted nannie and auntie where cut out of her life, and for no reason other than her step-dad's (+his mother's) spiteful jealousy!
Yes, I think love can be killed off, with so much cruelty!
You and me both Smileless with the long post 
and chocs tonight, for us all 