Jennifer Ruef lives in Chapel Hill, North Carolina. Each week, CNN profiles someone who has faced a dramatic turning point in their life. Do you have a story to share? Go to CNN iReport to share it, and you could be featured here.See more stories like this and share your own on CNN.com/TurningPoints

My first-born, Edison, is thin and quiet, with long, shaggy hair. In his eyes, I can see that he is wise beyond his years. My second child, Donovan, is solid. He is very cute and knows it. His hair is short, perfectly coiffed with gel. He knows the latest pop songs and performs them for us every night.

They are not twins. They used to be four years apart. It was proud big brother Edison, and his brother, "Baby D."

Edison died suddenly on July 9, 2011. He was 6 years old, and getting ready to begin kindergarten.

This past April, Donovan turned 6, and the lives of my two boys intersected.

It hit me harder than I expected.

Edison was a "micro preemie" weighing in at 965 grams. That's just over 2 pounds. His fragile body went in for life-saving surgery -- the first of six -- when he was 12 hours old. For 250 days, we sat in the neonatal intensive care unit at the Children's Hospital of Philadelphia, watching over our tiny baby. There were tubes coming out of every part of that itty-bitty body. The odds were against us. Please fight, Edison, we silently, and sometimes not so silently, begged.

At 8 months old, Edison came home. We did not know what the future held. Please sit. Please walk. Please eat. Please talk.

And he did. He ran. He talked. He smiled. And he laughed. Boy, did he laugh. When Edison was almost 4, he was doing so well that we decided to add to our family. Donovan was born on April 27, 2009. Edison called Donovan his baby.

Two years later, the summer before Edison started kindergarten, he died suddenly. We had gone to our community pool and while standing in line, I noticed Edison on the ground. I wish I could say the rest is a blur, but I remember every agonizing detail. The ambulance ride, the attempts at resuscitation, my screams. Holding that sweet child for 9 hours.

The nurse had put on the outer space pajamas we had carefully packed for bedtime after swimming. For BED time. Not this. After his death, we learned Edison had advanced pulmonary hypertension.

On April 27, 2015, we celebrated Donovan's sixth birthday. Until that point, Donovan had been my younger son, Edison his older brother. The milestone hit me harder than I could have imagined. Donovan will now reach ages beyond his brother: 7, 8, 9. Donovan will go to school, fall in love, live a full life. Seeing Donovan grow up has reignited my grief for what Edison did not and will not have.

I also ache for Donovan as I watch him shoot baskets alone. Or when he brings a picture home from school that he has drawn of his family. There are three. Why are there only tables for four at restaurants? A constant reminder of the missing link in our family.

Donovan will never again wear a pair of Edison's faded jeans, or one of his washed out T-shirts. Watching Donovan grow up in those clothes always carried a poignant remembrance of brotherly hand-me-downs, the normalcy of it.

In the years since Edison died, I have asked myself "What if?" and "Why?" If only we hadn't gone out that day. If I had not tried to progress him from his feeding tube to regular foods. I have sought book after book trying to find an instruction manual on how to grieve. It doesn't feel like I am doing it right. It doesn't get better. It gets worse.

Elisabeth Kubler-Ross famously wrote about the stages of dying and grieving. I studied them often as a social work student. I worked with grieving families. I thought I understood grief.

Now I realize that was like thinking you understand water because you've been to a lake. And then you go to the ocean. I have Denied, been Angry, Bargained and have been Depressed. There is also an A, Acceptance. At least, she said there is.

Recently, I came across an academic article about pulmonary hypertension in preemies. I reached out to the physician and author of the article. It was not the first time I had emailed a doctor I didn't know, in search of understanding. But this time was different.

Dr. Brian Hanna, a cardiologist and director of the pulmonary hypertension section at the Children's Hospital of Philadelphia, emailed back. We met for two hours in the cafeteria of the same hospital where Edison had spent his first 250 days. He painstakingly drew me diagrams and pictures, and explained that it was not a matter of "if," but "when." He told me there was nothing that could have been done differently. He gave me permission to examine my son's life, not his death.

After meeting with Dr. Hanna, I realized Edison had not died early. He had lived long. And boy did he live, showing us all to appreciate every day.

In his six years, Edison did so much. He woke up every day asking, "What we do today?" with eager anticipation. He often went to sleep declaring it "the best day ever!"

Driving home, I cried for both of my sons: For the 6-year-old who received all of my attention for the years he was here, and has continued to receive that attention in the years he was not. And for my other child, who has had half a mother for three years. Edison would be ashamed at how I am taking care of his baby. While nothing about this journey has been linear, I am working every day to be the emotionally available mother that our 6 year old, Donovan, deserves.

So, two boys age 6 have taught their mommy many lessons. Most of all they have taught me that your heart can smile and break all at one time and will do so daily.

My heart is just beginning to heal. But while still broken, I will smile for Donovan. I will smile for Edison. I will smile that my grief journey has been mine, and not like those written in books. I may not be doing it correctly, I may be doing it for too long, but like my children, I am doing it with everything I have.