AIBU To feel that they are taking advantage?

[Ohnotheinlaws]

So my sisters family moved into my parents as they wanted to get out of debt and save for a house of their own.
My parents gave them the run of the house and are living in a small annexe. It was agreed they would pay a small rent of around 200 / month.
It's been six months and they haven't saved a penny nor paid my parents any rent.
My mum is so sad that her house is a mess and all of the bills have increased and so now she is struggling financially in particular. I have lent mum a few hundred pounds over the last few weeks but AIBU to be annoyed that this wouldn't be the case if my sister paid the agreed rent? My mum won't say anything because of the grandchildren...
I try not to get involved in family dispute but I'm itching to say something...

It’s not your place to say anything really, but depending on your relationship with your sister I’d be saying something!

And telling her she should be paying substantially more (which she must know) so must atleast pay the minimum.

I'd get involved but that's the nature of my family. Your sister is very much taking advantage of your parents.

Maybe your DM needs you to help her stand up to this piss taker.

You mentioned parents and then it changed to mother. Is father still there and is he fit and well? If father is unwell and mother is his carer this is seriously taking advantage. Are they over pension age?

Could you report this as a safeguarding issue to social services. It does not look like she or they are able to stand up to the sister

Father prefers to be blissfully unaware of everything. In fact I don't think he will know about much about any of this ; my mum prefers it that way too (I never understood the dynamic but that's a story for another day... ). They are not above pension age, still each working full time to make ends meet. It makes me sad that they don't work as hard as my parents to make their ends meet. I do think she should be paying more, particularly when I consider our mortgage and bills! Glad I'm not the only one thinking they are taking advantage

Bugger that! Your sister is being outrageous! I wouldn't be able to hold my tongue, my business or not. Your poor Mum!

I try not to get involved in family dispute but I'm itching to say something...

But you are subsidizing your sister if you have given your mum money, so you are involved. Say something to her.

Andylion I agree, I just don't know how to word it...

You say
“Sis you lot are taking the piss! Move out you tight fuckers, mum and dads can’t keep affording to sub you.”

My mum won't say anything because of the grandchildren...
I try not to get involved in family dispute but I'm itching to say something...
You say
“Sis you lot are taking the piss! Move out you tight fuckers, mum and dads can’t keep affording
This job done .

thanks guys this has made me laugh. I'll procrastinate and hopefully find a pair tomorrow after speaking to mother about the situation ...