@cptartapp
With all the assets she has, your DM is going to be quite happy for you, in your middle years to be her carer in old age, and let you shoulder the burden of all the sacrifices, stresses time and commitments that entails. Indefinitely? She even let you move in preparation??! Wow.
Why did she see so much more of you and provide much more childcare for your DC when younger? I wonder how your brothers really feel about that?
Quid pro quo for the elderly care, I bet. Help the daughter more on the expectation - as always - that the woman will do the future caring. So cynical and not something done out of love and wanting to bond with the GC (who also, by extension, also don't benefit from inheritance and will wonder if any of that relationship with their GM was genuine or contrived to obtain elderly care). OP loses out on the will for nothing, as the childcare favours are cancelled out by the elderly care.
Unless there's been some massive inequality in upbringing that benefited the OP over and above her brothers (e.g., a fully paid for private education when they had only state and no other option), then all 4 have had the same life chances; but, as a woman, the OP has probably had the disadvantages that comes with her sex career wise. Adult children making different life choices is not a disadvantage, it's a choice. Marrying wealthy, agreeing to have a SAHP, having more/fewer children by choice (fertility issues not included), doing a job you love versus one that will pay you more, living in a cheaper/wealthier area etc etc are all life choices that do not need to be compensated for.
Of course there will be exceptional, out of their control circumstances that means one sibling has ended up far worse off than the others. (Although, more often that not, it's not a one off case of bad luck, but the cumulative effect of previous bad decisions). In that situation, I can understand a parent thinking they need to give them a bit more to lift them up. But completely cutting out a sibling who has done absolutely nothing wrong except make good life decisions, has a good relationship with the parents and done nothing to cause them angst or pain: awful and unforgivable. And unless the OP's mum has a few Faberge eggs in her personal belongings, that's what her DM is doing here.