If someone dies and leaves their estate to their two adult children and one of those children dies?

before probate is complete, is the deceased child's family (spouse or children) entitled to their portion of the estate/?

That adult childs estate now includes the recent inheritance. It now becomes property of his heir designates, via testate or intestate.

It depends on the state that you live in. Each state has a different set of inheritance laws

if the spouse or child is written into the adult childs will, then they would be entitled to that part of the estate

Assuming the deceased child's family are the Heirs to the adult child then yes. The heirs are determined either by the adult child's will, or the intestate laws of the state that the adult child lived in at the time of the parent's death.

But the 1st estate will have to be fully probated before the adult child's portion is determined. The adult child's estate needs to proceed with gettting an Executor of his estate appointed to oversee the activities of his parent's probate action.

Normally yes, as long as that adult child is alive at the death ( even one minute longer) then that adult childs estate would inherit on behalf of the adult child.

That is why esp in married couples who may have different payouts in thier wills, who actually died first if they both die in the same accident.

yes they should be unless there was a stipulation in the will about it.

My father passed and then his parents passed. His share of the estate and so forth was divided equally among myself and my siblings.

My mother passed and then years later my grandparents passed and when the probate is complete my siblings and I again will split my mother's share equally.

I don't know. I was going to answer that the deceased child's beneficiaries (i.e. of their will) would be entitled to their share of the half share, but now I'm not so sure after thinking some more. I'll be watching with interest.

Yes, if it happened before the will was done with probate.

Yes. In the event that an heir is no longer living to receive their inheritance, the inheritance then becomes property of that heir's estate to be distributed according to the heir's will. In the absence of the deceased heir's will, it will be distributed according to law - to that deceased heir's spouse and/or children. If the deceased heir has no spouse or children, their inheritance is then left to their next of kin. The law states what relation the next of kin would be.

It depends on the wording of the will ... if the will is silent, it depends on the state and estate administration laws governing it.

The original estate will be divided between the two heirs. If one of those heirs dies, even if it is before probate, their share of the estate will be put into an estate for the deceased heir. It does not go to the other heir of the parent's estate.

If that heir has a will, his share of the parent's estate will be divided according to the will. If there is no will, his estate will be divided according to the intestate laws of the state where he resided. The spouse and the children will inherit his estate in that case.