A mother’s tribute to her deceased 5-day-old son – the addition of a sandbox to his grave, so her older boy could continue to play with his brother – has quickly gone viral on Facebook, with more than 220,000 users sharing her photo.

Ashlee Hammac, 24, says she originally planned to decorate the gravesite of her son Ryan with glass pebbles, but then realized her older son, Tucker, needed his own place to mourn.

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“The more I thought about it, the more I wanted something my other son Tucker could be incorporated in,” Hammac told PEOPLE. “He always goes out there with me, and sits out there, and sings lullabies, and talks to him just like he was there. So I wanted it to be special for him too. His favorite thing right now is trucks.”

Hammac says Tucker has been cherishing these moments of interacting with his lost sibling, often asking his mother if he can go to “baby Ryan’s sandbox.”

After first posting a photo of Tucker playing in Ryan’s sandbox on March 2, Hammac said she has experienced an overwhelming outpouring of support from other mothers who have lost children. She says the virtual response has been particularly moving given her own difficulty in finding an outlet for her grief when Ryan passed away.

Ryan died five days after birth in October 2013 due to Hypoxic-Ischemic Encephlopathy, or HIE, a brain dysfunction that occurs when there is a lack of blood flow to the brain. Hammac and her family have now committed themselves to raising awareness of HIE through their new nonprofit Pages to Memories, an organization that donates supplies to neonatal intensive care units and provides emotional support to struggling families.

“I wanted to help. I wanted other people, because I know it wasn’t just me, to have someone to talk to to have a place they could depend on,” Hammac explained. “And I wanted to feel like Ryan was helping still, because in those five days he changed our family so much.”

Five Days In October

Hammac was 34 weeks pregnant when she started to lose her vision one day while out shopping last September. Concerned, the mother went to the hospital and discovered she was suffering from an extreme migraine – a migraine that would send her into premature labor.

Doctors were able to stop Hammac’s labor, but in the coming days she would go into labor four more times, leading doctors to green-light an early birth on Oct. 10 (her birthday). However, after being sent home to begin labor, she awoke the next morning with severe contractions and bleeding, and rushed back to the hospital, where she delivered Ryan shortly after 11 a.m.

Before Hammac had a chance to hold her son, or hear him cry, nurses took the infant away. Two hours later, a doctor informed her that Hammac’s placenta had ruptured during delivery, depriving her son of oxygen for several hours. Ryan was now being transported to a neonatal intensive care unit; he had a 1 in 8 chance of surviving.

As Hammac remembers them, the following four days at the NICU were a series of emotional ups and downs. By day two she was finally able to hold Ryan, but was quickly told that his prognosis was deteriorating. With Ryan mostly confined to his NICU bed, Hammac bonded with him through books, reading him stories day and night.

After days of treatment and numerous books, Ryan was taken out of his bed for an MRI, which showed no brain activity. Hammac says she and Ryan’s father were left with a difficult choice: “Any mom wants to keep their child, but the more I thought about it, I didn’t want to keep him if he couldn’t tell me if he was in pain. He couldn’t tell me if he hurt.”

Before saying goodbye to Ryan, Hammac introduced him to his 3-year-old brother, Tucker, who shared with his baby brother some of his favorite lullabies. Photographers from the nonprofit organization Now Lay Me Down to Sleep arrived, volunteering to capture the last tender moments between Ryan and his family. Many of these photos now hang in Hammac’s home.

While she was overcome with grief, Hammac says she was comforted by the fact that Ryan was able to give back in death; the infant’s healthy heart was donated to save the life of another baby. Hammac says she hopes to meet the other mom someday.

In the months following Ryan’s passing, Hammac has worked to keep her son’s spirit alive through Pages to Memories, a nonprofit that routinely donates books and blankets to NICUs so families can connect with their children much as Hammac and Ryan did during their five days together. Pages to Memories also provides a forum for parents who lost children, especially to HIE, to support one another.

Hammac says what’s most important to her is that Ryan continues to be a part of her family. For now, in Tucker’s sandbox, Ryan’s spirit endures.