Has anyone been a free caregiver promised a trust only to be cut out at the end?

Contrary to what many believe, an oral promise to make a will or trust is enforceable under California law.
California law provides for the enforcement of oral promises to make a will or trust.
Typically, a parent orally promises a child, a friend, or a caretaker some or all of their assets once they die, if the child, friend, or caretaker agrees to do something for the parent.

The “something” can be anything of value, but usually takes the form of the child, friend, or caretaker taking care of the parent until the parent’s death.

But if the parent didn’t get around to writing a will or trust that states the child, friend, or caretaker gets some or all of the parent’s assets after they die or if the parent never intended to write a will or trust reflecting the promise to the child, friend, or caretaker,the child, friend, or caretaker can enforce the deceased parent’s oral promise to give them assets.
The answer is ‘yes’.
California Probate Code section 21700, entitled “Contract to make will” has a provision that allows a person to establish an oral promise by establishing that there was an agreement between the parent and the child, friend, or caretaker that the parent would leave some or all of their assets to the child, friend, or caretaker after they died.

But this is where it gets a bit tricky. The procedural hoops one must jump through to make a an initial claim to enforce an oral promise to make a trust or will under California requires the following:
First, one has to pay attention to the applicable statute of limitations. The statute of limitations simply tells us how long we have to file a lawsuit to enforce an oral promise. The applicable statute of limitations for filing a lawsuit to enforce an oral promise to make a will or trust is one year from the date of death of the parent.
Before one can file a lawsuit based on a broken promise to make a will or trust, one must file a “creditor’s claim” in the estate of the deceased parent. The creditor’s claim is not difficult to complete and file, but if one fails to complete this step, and one year passes from the date of death of the parent, one is very likely barred forever from filing an actual lawsuit to enforce the parent’s promise.
Third, it’s still tricky. What if nobody has opened the deceased parent’s estate with the probate court? Can one simply wait until an estate is opened, whether that’s one or two years from now, and then file their creditor’s claim? The answer is very likely ‘no’. The applicable statute of limitations states that to enforce an oral promise to make a will or trust, a lawsuit must be filed within one year of the date of death of the parent. So if the probate estate is not opened, then one needs to file a petition for probate to open the parent’s estate with the probate court, file a creditor’s claim, and then file a lawsuit—all before the one year passes from the parent’s date of death.
Each of these steps must be completed before one can have their day in court to prove a claim based on an oral promise to make a California will or trust. If the one-year statute of limitations (calculated from the deceased parent’s date of death) is blown for any reason, the claim to enforce the oral promise is barred forever from being heard.

aldavlaw/practice-areas/litigation/abused-estate-and-trust-beneficiary-litigation/

A verbal contract isn't worth the paper it's not written on.

And the moral of this story is that if you choose to care for a family member, you do it for love, not money; from which it follows that if you are not able or willing to risk your own financial security in the process, you ought not to accept the task. Nobody forces you to.

I don't, as it happens, have a moral problem with family members caring for their relatives on a contracted basis: if that suits everyone, I see nothing morally wrong with what can be a practical, sensible approach. But in that case it needs to be dealt with in a practical, sensible way, which means getting the numbers written down and the contract signed.

What doesn't work is being noble about the cost to yourself of providing care, pretending the money doesn't matter, and then being in for a very nasty shock indeed when the will gets read. QED.

Cobrafang I understand your hurt and your sense of injustice. But at nearly 10% of a 2 million trust, you're saying your share of the estate of is approaching 200K, yes? Well. I wish my future lay in such ruins.

I think it's really important to only provide as much care as you can without it affecting your job, education etc. My grandfather was saying he doesn't know what to do with his money, doesn't want it just sitting around etc on the weekend and I refused to engage in the conversation but I did say that he should hold onto it because he might need it for care and that is very costly. He stopped talking about it - haha! This was my polite way of saying that I'm not willing to provide high end care when he has funds to provide for that. Hanging around in the hope of an inheritance would just the elderly person way too much control and also change your personality for the worse I feel. Those who take it on and are made verbal promises should get everything written up and made legal before they start.

Do you think perhaps your sister that does not visit, influenced your grandmother in some way? I'm not saying that your sister did influence your grandmother, but in some cases this does happen.

Consideration is what makes an unenforcable promise an enforcable promise.

A contract is a binding obligation between two or more persons predicted on a mutual understanding (“agreement”) of the parties. If one of the parties fails to conform to the obligations of the contract, that is called a breach of contract. Such agreements may be oral or written and can even be “implied” by the court in certain circumstances .
Contribution and Expectation,If one enjoyed the consideration you provided for years and you relied on the agreement to your detriment.
.While mistakes as to facts can lead a party to foolishly or mistakenly enter into an agreement, assuming that the party intentionally intended to enter into a binding agreement, the courts will normally still enforce the agreement since the other party relied on the commitment, and the longer the more in your favor.
Each party must either give up something or transfer some benefit to the other party before a binding agreement is created. This is called “consideration“ and ly means that the contract involves mutual obligations of the parties in which each side achieves some benefit from the other.
courts have held that if one reasonably relies on promised performance of another, and the other had grounds for knowing of that reliance, that the contract is enforceable even if the consideration is one way. the courts may enforce that obligation because you relied on my promise even though you had not obligated yourself to pay me anything or give me anything in return, i.e. it was a gift. This doctrine is called promissory estoppel.
The basic rule of law in the United States is that courts will award monetary damages for breach of contract. In certain unique situations the courts will actually order a party to do more than pay money.
Sure you can will your estate to anyone, but creditors come first.
There may not be much left after penalties and fees in that trust.

What are you seeking?

What kind of trust was it? Apparently it's not a revocable trust that provides distributions on death if payouts were allegedly to occur over the 4 year period (and thereafter)

If it's advice, this is a legal matter, assuming you have documentation to prove all the claims of inheritance. If not, it's just your word.

Also, what's your girlfriend's role in all this? Was she caregiver as well?

If the promise was in writing, you might contest things. You might talk to the sister, or some other trusted person to help draft and agreement that might be or equitable and begin to compensate you. 10% of 2 million is 200,000 and Im guessing that would be taxed more severely than if it was paid to you as caregiver salary. Hard to say what her motivations or understanding of what this is like from your point of view really is...sorry this is playing out this way, it sounds like it is legal though not at all right!