Just hours before 4-year-old Adalynn Sooter died from a brain tumor on June 3 at an Arkansas hospital, her big brother was at her bedside stroking her hair in the girl’s final moments.
“A little boy should not have to say goodbye to his partner in crime, his playmate, his best friend, his little sister,” the children’s father, Matt Sooter, wrote in a Facebook post alongside the moving photo earlier this month. “This isn’t how it’s supposed to be. But this is the broken world we live in.”
In the shot, 6-year-old Jackson rested his right hand on Adalynn’s head as the ailing girl held his left arm.
“It was a sweet moment, but not unexpected,” Matt tells PEOPLE of the siblings’ special goodbye. “Jackson has always been great with her and took very good care of her. He’s still a happy little boy, but he misses her.”
Adalynn, who the family called Addy, passed away at 1:04 a.m. that morning, 18 months after doctors found a tumor growing on her brain stem and diagnosed the girl with diffuse intrinsic pontine glioma (DPIG).
“We miss her terribly, but we’re also at peace knowing we did everything we could to try to help her and that she isn’t in pain anymore,” the grieving father says. “It was only, ‘See you later.’ We’ll see her again some day.”
Doctors delivered the diagnosis on Nov. 12, 2016, and gave Adalynn just months to live. The Rogers, Arkansas, girl shocked medical officials with her survival and Adalynn’s parents, Matt and Chandra, were pleased when the girl’s tumor began to shrink with size.
Last month, Matt called Adalynn’s survival “purely incredible.” However, he said then that he knew his daughter likely wouldn’t live much longer.
“While we’re doing everything we can to change the outcome we don’t expect to win this fight. We haven’t given up, but it seems we are losing the war,” he told PEOPLE at the time.
In the days since Adalynn’s death, family and friends have posted messages of condolences on Matt and Chandra’s Facebook pages.
Adalynn endured dozens of radiation treatments after the diagnosis. And when doctors told Matt and Chandra there was nothing else they could do for the little girl, the family sought an experimental treatment offered in Mexico.
For nearly a year, they took the little girl to Monterrey for treatment and Matt said a single trip could last up to 12 days. Travel and medical expenses cost the family more than $200,000.
The treatment hadn’t been effective in the weeks leading up to Adalynn’s death. But Matt told PEOPLE last month that the family was prepared for the worst.
“While we don’t look forward to a future without our little girl, we don’t fear it,” he said.