@NewDOOFUSfor20
Yes your dsis is clearly not thinking straight, and what she is demanding is clearly very unreasonable, but I kind of get why she is a bit pissed.
I honestly will never understand why parents do this to their children, grown or otherwise, give absolutely EVERYTHING they can to one child but absolutely nothing to another.
I get that situations change but it's still a kick in the fanny when you see your sibling living what is perceived as a charmed life through the help and support of parents, when you are left to struggle.
Would your sister have had the baby if she thought for a second that all help offered would be retracted?
It's very easy for you to mock her ill feeling, you've benefited massively from your mother's childcare so couldn't possibly understand the struggles.
But she can still fuck off with the "paying half of my childcare" shit, that really is nuts.
All of this is what I think. (Saves me typing it all out - thank you!)
I also think it's a bit shitty when the parents do something big, and bend over backwards for one sibling and not the other(s,) and of COURSE the sibling who doesn't have the favours is going to feel pissed off and angry and upset.
I have even known a few instances where the parents give one sibling a deposit for a house, (like £40K) and give fuckall to the other(s.) Very poor form IMO.
However, to ask you @Whatevernext2 to cough up for half her childcare fees is ludicrous to the extreme! You have to say no of course, and tell her that her beef is/should be with mother, not you.
Although, your mother's circumstances have changed and she isn't doing any of this on purpose. So I do get it from your mother's point of view. But as 'newdoofus' said, your sister's anger is understandable.
I don't envy any of you in this situation, and I don't have any advice, I'm sorry. It's really tricky.