Orchid I'm sorry hut I am confused too.
1. Last christmas my sister-in-law turned up at my mother-in-law's house after my father-in-law's passing.
- Presumably your sister in law is their daughter?
2. Backstory: MIL and FIL fell out over 30 years ago which resulted in FIL banning SIL from house. As he's recently died, SIL has come back in a group setting (ie. me, husband, BIL, and children)
- Why was SIL banned when it was MIL/Fil who fell out. What had SIL got to do with the problem?
3.*As he's recently died, SIL has come back in a group setting (ie. me, husband, BIL, and children). I feel awkward as I've actually only been in her company about 8 times in nearly 30 years*
- did you see her during the 20 years she was banned?
-does your husband feel awkward too? This is his brothers wife I think. Did he get on with her prior to the banning from her parents?
4. Came into the room very huffy and never spoke to me and my husband
- did you speak to her? Say hello? Ask how she was?
- if she ignored you completely I suggest you carry on regardless, offer to make a cuppa if making ons for yourself etc.. in other words just carry on and ignore her ignoring!
5. She told her daughter on her wedding day 'why are you marrying into this family for?'.
- so this is just an example of her bad behaviour and why you dont like her?
6. Told my MIL that she is not fit to babysit hergranddaughter. This is not my issue
- was this during this visit at Xmas? Or is this another example of her behaviour and why you don't like her? And not your issue so why are you mentioning it?
7.*however given the context of her outbursts suddenly she is making a home visit when we turn up after a disappearance of 20 years at in-laws home. I'd like some advice about how to handle her because we are not personal friends*
- as suggested above. Carry on as normal and ignore the ignoring.
- but if she is directly rude do not tolerate it ..."did you mean to be rude when you said that?" ..."Its a shame you feel like that. It's not my view though" ..." What evidence is there of that" ...those type of responses depending on what said keep you in control and make clear it won't be tolerated
BUT - what is your husbands reaction to her behaviour, he should be stepping up as well if directed at you and his mother surely.
8.*she had used my london flat like a hotel and then made sure that we weren't invited us to niece's wedding.*
- so another example of why you don't like her and her bad behaviour?
- was this during the 20 year ban from her parents house?
Weirdest thing was that BIL showed divorce papers to my husband and she is staying at a different house with no wedding ring on
- their choice, nothing to do with you!