It's another inheritance one...

I think if Mary had no will it would all go to Jane? So in many ways, that’s the “standard” / starting point.

I was in the 50/50 to the grandchildren camp until you explained Mary’s logic

she’s thought about it wants her money to help her remaining living child. That’s perfectly valid. Her logic that GCs have had a good start and have a long time to save for retirement is also valid. She wants to die knowing her daughter is taken care of. The GCs need to back off and not make her twilight years difficult.

Perhaps Sarah's share could be split three ways between her husband and two children. That wouldn't really be fair on Jane's children though.
Another idea would be to split it 6 ways, with each child, Jane and Sarah's husband each getting a share.
Or stick to the original plan, but Sarah's husband gets her share and each grandchild gets a few thousand each. They could hardly say that wasn't fair as that was the original plan. If Sarah's husband chooses to give the money to their children, that's up to him.

Alternatively Mary could just decide the money grabbers among them are getting nothing and leave their share to charity.

Difficult one. Had Sarah lived she would likely have spent a significant portion of her inheritance (pension top up, social care, cruises etc) so her children would likely have only have got the equivalent of 1/8, as they are now. They may have got less.

There is a chance that Jane may not spend much of her share and her DC will get a a further portion of her inheritance eventually - or she may live to 85 and all of it get eaten up in social care.

If Mary’s plan is a) to ensure Jane is looked after in her old age [and is hoping she will have a lovely, longer life as a result of that money supporting her] and b) aims to treat the GC all equally, then her will as it stands is perfectly fair as it ensures all 4 DGCs get a set sum now. Under the old will (50/50 Jane and Sarah) had Sarah lived, they could have got absolutely nothing at all once the mothers had spent their way through it.

It’s hard though. From the PoV of Sarah’s dc, it’s as though Jane’s benefitting from their mum’s death.
I think it’s really sensitive, because inheritance isn’t about money it’s about value. For various reasons DH won’t be inheriting from his parents, and so neither will our DC. It feels like despite being good loving family members for decades, it doesn’t matter. Someone else is more important. Worse, we’ve been paying into a pension for the other person, recognising their need, and would have had no hesitation in making sure he was ok. It feels as though we can’t be relied on, aren’t valued, and aren’t as much family as the other. DH is sanguine but I begrudge it a bit!

Unless circumstances are very extreme, I think the standard is best. Circumstances can change a lot after money is distributed. The emotional impact can be significant (especially on top so losing a parent early).
Jane’s retirement shouldn’t be planned around an inheritance. Mary could live another twenty+ years and the actual inheritance could end up being tiny.

I think it should go 50% to Jane and the other 50% should be split between the kids of the sister who died. In my view anything else is unfair. But it’s not my money and only Mary can decide!

Well obviously it’s Mary’s to do with as she choosing. I agree arguing over someone’s estate when they’re still alive is horrible.

I don’t really think it’s that unfair.

The surviving dd (Jane?) will likely spend the money during her retirement it seems? So this way, the grandchildren all benefit to the same amount. As the deceased daughter (S) was likely to have done the same, her children wouldn’t have have any inheritance from grandma if S had lived.

So this way, all the grandchildren get something. And it’s something that wouldn’t ordinarily have expected to have.

The other way isn’t unfair as such either, but clearly Mary wants to give some to all of her grandchildren, not just half of them. As pps have said, she could have left it all to her surviving daughter.

This is the correct way to do it.

Sarah is deceased, she doesn't have a share.

How interesting. After your first post, OP, I thought it was wrong that just because their mother died (!), Sarah’s children shouldn’t have salt rubbed in the wound by inheriting less. But reading Mary’s reasoning…clearly she sees her duty as being to her children, and wanting to leave a token something to grandchildren. Seeing as she now only has one child left, she wants to do as best as she can by her remaining child. After all, she might be thinking, the grandchildren are young and have their whole lives to earn more.

I see the point, and it’s actually a very valid one imo. Is Mary very close to or fond of her grandchildren?

I think it's fair as quite often the only surviving child is sole beneficiary. This was my situation. My brother's wife and his step children are fine with this. Admittedly, the step children were grown up by the time my brother and SIL married. I have one DC, he wasn't an adult when my parents passed away. I've invested part of my inheritance for him.

I think this is exactly right. This is what my parents have put in their will and told me and my 2 siblings. We all think this is fair.

My parents are very open about wills as they have seen too many people fall out about such things.

My in laws are the opposite and my husband doesn’t even know where their will is held or who the executor is 🙈.

Agreed, if one of my beneficiaries so much as questioned my will I'd cut them out - easiest way to resolve!

I think maybe a little fairer would be 20% each to daughter and GC - as if daughter spends it all, her children might not get any of it?

Sarah’s share should be split between her children. I feel bad for her children, they’ve lost their mum and now also have less money going to their side of the family as a result

If she had left her will as it was Sarah’s DC would have received their mum’s 50% under most standard wills. I inherited twice this way as my mum died young.

Mary has affectively halved what Sarah’s DC will receive. I think you need to think very carefully if you deviate from the standard as it can come across as spiteful, even if it can be framed as fair at first glance. It goes beyond the monetary value, it somehow erases Sarah - even if it wasn’t mean that way.

So say it’s 100k. Originally it would have been-

£5k each for gc
£40k each for Jae and Sarah

Now it’s-
£50k for jane
£12.5k for gc

So grandchildren are actually getting more than they would have if their mother was still alive?

If Jane died before Mary would the inheritance be split equally between the grandchildren?

I suspect the issue is that everyone was informed of the previous will and therefore some people are now aware that with the changes they will get less than they would have previously while others will get more.

my parents did similar - made wills, explained why, then totally changed their mind. It does set up expectations which are then changed and it’s hard to avoid the idea that the person/people doesn’t like you.

I think this is the fair approach. Also acknowledges that those gc have been without their mother for some time, which must be difficult.