Wills almost always provide for per stirpes distributions to children. That means if any child is not alive at the time of death of the person signing the will the portion that would have gone to the deceased child gets split between the children of the deceased child.
For some reason, Fred Sr. cut Fred Jr.'s kids out of the will by saying his estate would go only to his living children. Again that is unusual, but it's not unheard of. Maybe he cut them out because they were brats and alcoholics? Her behavior here would certainly suggest that about her.
That said, the only issue is whether the non-disclosure agreement prevents her from publishing book. If such an agreement exists, she will be bound by it and will be prevented from publishing. There is no First Amendment issue here regardless of what her sleazy attorney says.
Her brother suffered from cerebral pAlsy. She and her brother sued. Settled out of court. Med ins reinstated. I believe concern about undue influence that Trump influenced his elderly father.