My uncle passed away and his will reads that his siblings are to inherit half of his trust. His deceased wife's family will inherit the other 1/2. Since my mother is the only living sibling, does it automatically go to her? The attorney mentioned the "family tree." Since my mother's deceased sister has two living adult daughters, will they receive their mother's portion even though they are not listed in the will?
I would say, this may take time to sort out because of the wording "deceased wifes family" again what constitutes family in your State. I think it should have been more descriptive like "deceased wife's daughters. If one or both daughters are deceased their share will go to their children".
But then again, different States, different laws. And Wills and Trusts are two different things. People use Trusts to help protect assets from probate. Wills, depending on the size of the estate at time of death, may need to be Probated.
"Some very close relatives—meaning a surviving spouse and sometimes children or grandchildren—have the right to claim an inheritance, and in some cases this can override what it says in your will."
Source: https://www.nolo.com/legal-encyclopedia/inheritance-rights-29607.html
We are not attorneys on this forum, so your final and most accurrate answer should come from an attorney for the deceased's state.