Is behaviour of Narcissist Mother affecting child and what to do...

Hey All,

My partners ex wife is by all accounts a narcissist... and I recently listened to a fairly upsetting voice recording that she sent my partner, because their daughter (aged 6) had hit her mum with a soft cuddly toy (I know right!!!!) - whereby she was saying 'Im calling Daddy because you hit me and because you have been naughty and thats why you cannot play on your iPad' and Daughter was wailing in the background hysterically.

Daddy asked her to calm down and what was wrong and daughter said she felt sad. She felt sad because mummy had told her she wasn't allowed to play on her iPad any more and took it away from her, so she threw a cuddly toy at her mum and her mum claimed it hit her in the face and hurt her.

After the hysteria had calmed... daughter was chatting to Daddy and Mum kept intervening and interrupting and re-iterating her version of the events.

its one of several events that have concerned my partner and myself (an older one was when Mum kicked out with her legs at daughter aged 3 and she toppled over landing on her front).

Mums mood swings are quite severe and she can go from 'normal' to scary and intimidating raging anger in moments.. and then back to 'mummy loves you so much baby girl'.

My partner only gets to see his daughter every two weeks for a whole weekend - but would ideally like her to liv with us - although I'm sure thats as rare as unicorns...

Does anyone have any experience in how to put a case together, gather evidence, tips on how to co-parent with a narcissist mother (the resident parent)

Im guessing that the Authorities have a certain threshold or scale of what they consider to be abuse... and probably narcissistic behaviour or coercive controlling parenting doesn't meet it... so we probably don't have much choice other than to stand helplessly on the side lines witnessing these events when they happen.

Daughter is a great kid - well behaved and never aggressive or violent or angry with us. If anything - the opposite.. if we have to tell her off she runs and hides... and we then have to coax her out and explain what she did wrong or just ignore her until she comes around.

Mum has a history of aggressive and passive aggressive behaviour and thats why he left her... 

but he feels terrible because his daughter is stuck there with Mum and there seems to be little he can do about it.

We can't realistically go for 50/50 joint parenting as we live 100 miles away so schooling would be impossible. 

Are we really only left with one option - to watch and try to counter any negative issues by giving her as much love and calm and safety when she is with us?

All tips welcome!

Ive never been a step parent before but do have experience of narcissists thanks to my own ex partner!