Adult sister emotionally manipulating my Mum

[LouiseRuf13]

I have come here as I am not sure where else to turn for advice. My sister who is 21 lives with my Mum who is very emotionally vulnerable. My mum had a breakdown and attempted suicide several times following the breakdown of my parents relationship. My sister has had two relationships, where I know she was very controlling and would not allow her boyfriends to see their friends or family. If an attractive woman appeared on a television screen she would make them turn away. I felt genuine relief for her partners when they eventually managed to break up with her. I feel awful that I feel this way about my sister but she is one destructive force.

For a couple of years now she has lived with my Mum. They are both key workers and have worked really hard throughout the pandemic. My sister has witnessed people dying from the virus yet still travels regularly to meet new men and spend the night with them, even inviting strangers into my mums house to spend the night. I know I could not tolerate this if I were her mum but when I speak to my mum she tells me if she challenges the behaviour but she can't say anything as my sister will call her a "fucking bitch" and a "shit mum" and smash the house up. I have told her to be clear about the boundaries and threaten to kick her out if she doesn't comply.

The most recent update is that my sister travelled to meet a man she'd never met 150 miles away late at night on a train and came back traumatised saying she had been assaulted. I am so torn between wanting to support her but being so blinded by rage that she would even consider putting herself in this position at such a time. She is also a compulsive liar. I have no idea what I can do to help. Please advise. sorry for the essay!

[LouiseTrees]

Does your mum own the house? It’s relevant to my two/three possible suggestions.

[LouiseRuf13]

She does yes

[LouiseTrees]

I was kind of hoping you’d say it was a council house but in your mums ownership fully I guess I’ll try think of some things. Okay so suggestion 1 ( bit least preferrable) is that she ties the rules of the house to inheriting it and she inherits a lower share if she puts your mum at risk. Option 2 is that your mum says she’s selling the house to move to sheltered living or similar ) doesn’t actually have to do it and therefore suggests your sister lives elsewhere. Or she says she’s selling the house in general ( can use painful memories as an excuse) and they can look for a new place together but like keeps asking why your sister doesn’t want her own space or hunting “ actually this is too small for me but would be good for you”.

[LouiseRuf13]

I think that you're spot on with the gentle suggestions of moving out. She is already in a very tiny 2 bed so would have to think about the reasons for downsizing, but the fact my sister does not pay rent might help.The inheritance factor is something I had not ever thought of. Thank you!

[LouiseTrees]

I think she should say due to her mental condition she wants to go into a one bed assisted living flat. She doesn’t have to actually do it.