It sounds like the decree severed it from the original family. So it will go to the divorcee's family.
There are Oklahoma Statutes that show intestate succession which would apply. Blood relation for purpose on inheritance is not restricted to children. Surviving Siblings, Parents, Grandparents come into play.
This will also answer your second question. (but she needs to take action if of sound mind)
Here is some of the text from the statute.
B. Beginning July 1, 1985, if any person having title to any estate not otherwise limited by any antenuptial marriage contract dies without disposing of the estate by will, such estate descends and shall be distributed in the following manner:
1. If the decedent leaves a surviving spouse, the share of the estate passing to said spouse is:
a. if there is no surviving issue, parent, brother or sister, the entire estate, or
b. if there is no surviving issue but the decedent is survived by a parent or parents, brother or sister:
(1) all the property acquired by the joint industry of the husband and wife during coverture, and
(2) an undivided onethird (1/3) interest in the remaining estate, or
c. if there are surviving issue, all of whom are also issue of the surviving spouse:
an undivided onehalf (1/2) interest in all the property of the estate whether acquired by the joint industry of the husband and wife during coverture or otherwise, or
d. if there are surviving issue, one or more of whom are not also issue of the surviving spouse:
(1) an undivided onehalf (1/2) interest in the property acquired by the joint industry of the husband and wife during coverture, and
(2) an undivided equal part in the property of the decedent not acquired by the joint industry of the husband and wife during coverture with each of the living children of the decedent and the lawful issue of any deceased child by right of representation;
2. The share of the estate not passing to the surviving spouse or if there is no surviving spouse, the estate is to be distributed as follows:
a. in undivided equal shares to the surviving children of the decedent and issue of any deceased child of the decedent by right of representation, or
b. if there is no surviving issue, to the surviving parent or parents of the decedent in undivided equal shares, or
c. if there is no surviving issue nor parent, in undivided equal shares to the issue of parents by right of representation, or
d. if there is no surviving issue, parent, nor issue of parents, but the decedent is survived by one or more grandparents or issue of any grandparent, half of the estate passes equally to the paternal grandparents if both survive, or to the surviving paternal grandparent, or to the issue of any paternal grandparent if both paternal grandparents are deceased, the issue taking equally if they are all of the same degree of kinship to the decedent, but if of unequal degree those of more remote degree take by representation and the other half passes to the maternal relatives in the same manner; but if the decedent is survived by one or more grandparents or issue of grandparents on only one side of the family, paternal or maternal, the entire estate shall pass to such survivors in the manner set forth in this subsection, or
e. if there is no surviving issue, parent, issue of parents, grandparent, nor issue of a grandparent, the estate passes to the next of kin in equal degree;
3. If the decedent leaves no spouse, issue, parent, issue of parents, grandparent, issue of a grandparent, nor kindred, then the estate shall escheat to the state for the support of the common schools; and
4. For the purpose of this section, the phrase "by right of representation" means the estate is to be divided into as many equal shares as there are surviving heirs in the nearest degree of kinship and deceased persons in the same degree who left issue who survive the decedent, each surviving heir in the nearest degree receiving one equal share and the equal share of each deceased person in the same degree being divided among his issue in the same manner. The word "issue" means lineal descendants.