Her Mother could sponsor her to immigrate but that will take many years. Sounds like your Mother is or will be a Permanent Resident? Also assumes sister is single.
That might be difficult your sister can certainly apply for. B2 but the better bet would be for you to go over and accompany her back.
Is this an Air Ambulance situation?
Excellent new NY is good to go for migrants
https://www.theguardian.com/us-news/2023/sep/07/new-york-city-immigration-bussing-comments-mayor-eric-adams?CMP=Share_AndroidApp_Other
It has been some years but people I know who had travelled to Israel had to get a second passport if they wanted to travel to Muslim, well some at least, countries. I have not heard of an issue the other way around.
They voted for inclusivity as an organisation, and she took them up on it.
So the Judge basically said well you were the ones who defined women as including men so leave me out of it.