If all was given to my mother-in-law, prior to the death of my father-in-law, is his will voided?

I assuming your sister-in-law was not named as the sole heir in your father's Will. The house and all in his estate would go as the Will states. It is not too late to probate your father's estate/Will as title to the property can not pass without there being a probate,unless it was held in joint tenancy. As to her estate, it would go equally to her children; if those children had signed a written contract [transfer of property has to be in writing unless you can show detrimental reliance], the their share of the property would go as the contract states.

This is too complicated for a LawQA answer, hire an attorney or someone to review all the documents.

A will does not have a statute of limitations. Furthermore, if I understand you correctly, the father's will said everything would go to his wife, and that is what actually happened. So, I am not sure how it would help to "go back to the father's will." The house and all the other property needs to be distributed through the mother's estate. Because she had no will, the probate court would ordinarily divide the estate equally among her children. You should talk to a local probate attorney to help you figure out whether the probate court is more likely to enforce the agreement among the children or distribute the property equally.

The will provisions of the deceased controls, not an after agreement among alleged heirs.

There is no statute of limitations on your father's Will. An agreement among'st the beneficiaries can be approved by a probate court, but probate would still be necessary. You should review your entire situation with a probate attorney. The title of the assets and the provisions of the Will are important to review.

If father-in-law's will said "all to my spouse," then that's done: mother-in-law inherited all. Father-in-law's will does nothing more, all of mother-in-law's estate (including what she inherited) passes in her estate if no will, then intestate per statute.

Your father-in-law's will left everything to his wife (your mother-in-law). On her death, if she had no will, her estate would be distributed among her heirs at law which, in this case, would be her children in equal shares (provided, of course that she did not remarry after her husband's death). At the time of her death, her husband's will would have no effect because its terms would have been carried out.

If your father-in-law had a Will then his assets would be transferred as directed in the Will. If the house was held solely in his name then a probate should be opened to transfer the house to the Mother-in-law as directed in the Will. If the property was owned in joint tenancy by your in-laws then it is in your mother-in-law's estate as the surviving joint tenant. If your mother-in-law had no Will then her assets would be divided equally amongst her children, with the descendants of a predeceased child sharing the portion the would have gone to the predeceased child if alive. A probate should be opened for the mother's estate to transfer the real estate and distribute the other assets. If the heirs equally divided the assets of the mother's estate the distributions could be made in either in-kind (delivery of the actual thing) or in cash. The real estate could be distribute to one and the other assets divided among the others. Such a settlement agreement can be made amongst the heirs. Acceptance of their agreed share would indicate the agreement was approved. A probate could be opened and used to ratify the settlement agreement, if it can be proved. The Father-in-law's will can be probated and the assets delivered to the Mother-in-law's estate. The Mother-in-law's estate would then be probated to distribute the property to the heirs.

Father is out of it because it went to his wife. Assuming there was a probate of mom's estate, that should handle it. If not, then it should probably be probated to get the title of the house out of the estate. You really need to talk with a local probate attorney to figure things out.

Your father-in-law's estate is settled and closed and does not apply to this situation. As your mother-in-law did not have a will, the intestacy laws of the state she resided in at the time of her death will determine who gets what. Generally, that means that since there was no surviving spouse, her estate would be divided equally between her children, both natural and adopted. While her children may have agreed upon how the estate was to be distributed (unequally, it sounds like), it is each child's right to challenge that distribution and ask for a court order to distribute the assets as required by law.

Now that it is really messed up you will have to hire an attorney to straighten this out.