My siblings are wanting to split everything equally with no reimbursement for me, even though I took care of Mom. Can they do that?

What are they wanting to split?

If you are talking about an estate after your mother passes away, the will governs how any assets - money, house etc - are distributed other than specifically titled bank accounts or life insurance policies with a specific beneficiary. If you expect to get paid as a caregiver, you have to settle it up front with parents because the siblings missing to take care of someone are not going to be generous to you.

Has she died?

What the will says governs the split.

If she is still alive, it is entirely possible that her care for the rest of her life will leave nothing to split. That is a very common situation, so I hope no one is counting on a lot!

I'm going to sound catty, but 7 months is nothing, there are many on this site who have been in a similar situation after putting their lives on hold for years.

Is there an option to explain (and document) the cost to you and ask your sibs to contribute part of their inheritance to cover your lost wages and expenses?

It sounds like your mother recently passed and you are dealing with the estate. Since you lived with your mother, your siblings may have the idea that you had free rent during this time, and that should be enough. But really, how many of them would work 24/7 for free rent? Still, it is hard to get around that mentality. The others are right that the assets will be divided according to the will. If your siblings chose to give you a larger share, it would be kind, but they don't have to do that.

The only sure time of getting paid is while you are giving care. The parent can contract to pay the caregiving child a certain amount. After death that opportunity is lost.