Super fussy / possibly OCD sil coming to stay!

[mashedbananaontoast]

My brother & Sil are coming to stay tomorrow after having stayed at my Mum's for the past week.
Sil has always been very demanding & brother has always been very accommodating to her "needs".

Examples of past behaviour:

1. Yesterday made my (75 yr old mother) walk around trying 4 different restaurants for the flavour soup she wanted , nothing pleased her so she went to McD's. Mum too polite to say she was tired, brother too downtrodden to put foot down.
2. She refuses to get into sync with her jet lag with her guests & lies in til afternoon & then keeps people up half the night with her clonking around & talking.
3. Makes travelling anywhere hard as she doesn't like sharing "car air" with other people.
4. Talks incessantly about topics for hours that interest her, & gets cross when anyone tries to change the subject.

This is just the tip of the iceberg.

AIBU to not accomodate every need whilst she is our guest. We have 3 young dcs and we just can't drop everything to please her. Where do you draw the line between guest is pandered to & guest also has to fall in line & be polite?
But if she is OCD how do we handle her everyday stresses?
Help!

Doesn't make any difference even if she has got MH problems - she shouldn't be pandered to in this way. Four restaurants? That's ridiculous!

When I said take the piss I meant in the nicest possible way... Although reading it back it seems a bit harsh. Just that my sister does this and DH and I make light of it - we say we have to take 'shifts' listening to her as it doesn't matter who she's talking to - one of us can leave the room and the other come in and she doesn't stop for air! She laughs about it with us, and recognises what she does. She still does it but it's now easier to say 'and breathe' or change the subject.
I didn't consider AS so apologies if I offended anyone. My sister is not on the AS but can be quite introspective and behaves a lot like OP's sil. But she's also my best friend and I love her to bits.

It's just best not to pander

I have OCD but it is me who suffers (and dh) not other people.

Ime OCD sufferers usually try to hide it, the ones who demand are usually not true sufferers but just self-absorbed.

And if it is ASD August?

Sorry, August, posted before reading to the end. Trigger happy fingies and a big gob, here!