Sister having an affair

[Mugglenet]

My mum walked in on my sister having an affair last week! She obv denied it but my mum knows what she saw and is disgusted .
My sister basically attacked my mum verbally and was manipulating the situation to make it out that she was a victim being accused in the wrong. My sister is a very vindictive manipulative person and can turn any situation around on you. She is not a nice person.
My mum read her the riot act and hasn't heard from her since.
My poor mum is heart broken as she is keeping her grandkids from her and she doesn't know what to do.
Obv my sister shouldnt get away with her behaviour but she is punishing my mum for some thing she didn't do wrong.
Any advice would be greatly appreciated.

How did your mum walk in on it?! Did she walk into your sister's bedroom or something?!

My poor mum is heart broken as she is keeping her grandkids from her

Has your mum contacted her or her dh at all. Has she asked to see her grandkids?

When it all comes out she will be expecting your dm to help with childcare when she is a lp I would expect. ....

She found her in the front sitting room and she slammed the door in her face. She was half naked with this man my mum didnt know in there.
However I do know who he was and there has been speculation about them in the past.
The eldest grandchild is 18 and he stays with my mum regularly. She offered to take them for lunch yest to be told mum says I have to go home and she lifted him at 9am

My sister is a very lucky person 3 wonderful kids. A fantastic husband and both have great jobs, however she is never quite content with what she has. Someone else's grass is always greener