"Legally, unless there are other directives, it's the biological father, not the older children," said Rauch. "You can't leave custody in a will, but you can make your wishes known."
Edwards told ABC News in 2007 that the family didn't "prettify" her impending death in any way.
"This is the way it is," she said she told her children. "But we also said, at the same time, you know, everybody who's sitting at this table who's not going to die, raise your hand. And they realized that we're all going to die. But we are also extraordinarily honest with them because there will come a day when they're going to have to accept that cancer has, at some point, taken me."
Many children as young as Emma and Jack won't feel the "enormity" of the loss until they are older and "re-experience" the pain during pivotal moments in their lives -- as a teenager picking out a prom dress or learning to drive, said Rauch.
As adults, common themes expressed by those who have lost parents are that the family was disrupted, that the family had to move or became poor, and how they found it distressing when well-meaning loved ones took away photos of the parent and didn't allow them to talk about their loss.
But having multiple caring adults around can help children find someone who can help them remember the parent.
"Grief is a process and not a one-time event," said Rauch. "Children grieve over a long period of time, and it comes in waves."
Symptoms of grief include excessive crying, tantrums and regression in behaviors, according to Dr. Ari Brown, a Texas pediatrician and author of "Expecting 411."
Her advice to the surviving parent is to tailor the approach to the age of the child, not to hide your own grief, don't say death is going to sleep and let the child grieve.
"It's okay to let your child see you cry," she said. "No one ever likes having a conversation about death, but the surviving parent needs to be candid about the circumstances of the illness or death and about their own feelings about it."
Common reactions to grieving in young children include anger at the surviving parent or family members who "let" the family member die; denial of death and the hope the parent will return; and concern that the child has caused the parent to die.
The relationship between the dying and surviving spouse can also affect a child's well-being, according to child development experts.
Elizabeth Edwards wrote about her decision to divorce her husband after his infidelity and betrayal in her 2009 book, "Resilience: Reflections on the Burdens and Gifts of Facing Life's Adversities" (at the time of her death, they were legally separated) but took care to emphasize on her book tour that her husband was "still family" and her children "would need to have a good relationship with their father" once she was gone.
Rauch said that although families such as the Edwardses can be "fractured," whether by scandal or separation, what is most important is the love and respect the dying and surviving spouse convey about each other to their children.
In Elizabeth Edwards' final days, John Edwards had moved back in with his family.
"What people on the outside think is not always what is going on in a family," Rauch said. "And when looking at happy families from a great distance, there are many secrets and complications."