Story highlights 11-year-old Abdulrahman lost his leg during a rocket attack is Syria

Abdulrahman's brother Omar promised his younger brother that he would walk again

The two brothers navigated the dangerous trek across the Turkish border to get help

U.S.-based group is working to get Abdulrahman the medical care he needs

It was around 6:30 in the morning. The air was crisp, the farmers had just watered their fields -- corn perhaps, Omar doesn't entirely recall -- and the ground was muddy, slippery and uneven.

There was a pack on his back, a bag slung over each shoulder, and cradled in his arms, the frail body of his 11-year-old brother Abdulrahman.

Abdulrahman, the baby of the family, couldn't walk on his own. His left leg was blown off in late July.

The last words of the driver who dropped them off echoed in Omar's mind: "You're on your own now."

It was as far as the car could safely take them in Syria, a few hundred meters from the Turkish border.

Omar's back ached, his arms in agony. He focused on putting down one foot after the other, struggling to keep his balance.

He looked down at Abdulrahman's face every few minutes and tried to smile reassuringly.

JUST WATCHED Iran behind drone attacks in Syria? Replay More Videos ... MUST WATCH Iran behind drone attacks in Syria? 02:05

JUST WATCHED U.N. High Commissioner speaks on Syria Replay More Videos ... MUST WATCH U.N. High Commissioner speaks on Syria 03:39

JUST WATCHED Airstrikes pound suburbs of Damascus Replay More Videos ... MUST WATCH Airstrikes pound suburbs of Damascus 01:16

"The only thing that I could think was to arrive, that whatever I was going through, once I arrived it was all going to be OK," Omar said.

For the safety of the brothers and their family back in Syria we are omitting their last name, specific locations, and other identifying details.

"There were fighter planes and there was a rocket that hit close to our house," Abdulrahman says quietly about the day he was injured. "I went to see what was going on and another rocket hit."

He doesn't say much beyond that; at times simply nodding or smiling sweetly, or seemingly lost in his memories.

Tears slowly overflow out of Omar's eyes. He slowly wipes them away as he looks down at Abdulrahman.

Omar, 21, was sleeping when the first rocket hit. His mother, panicking, came running into his room.

"My mom woke me up saying, 'Stand up immediately.' She said Abdulrahman went out and the plane is roaming, is circulating above, you need to get him back to the house," Omar tells us.

He was too late.

"I kept running, the first guy saw Abdulrahman injured and he said 'Catch up to your brother, he's about to die.' I can't control, I ran, ran, ran. When I got there, they told me the ambulance has just taken him."

Abdulrahman doesn't speak to us about those moments.

But Omar says his brother recounted how people were running away. "He was wounded, and he began shouting, 'Isn't there anyone to carry me?'"

JUST WATCHED Assad performs Eid prayers Replay More Videos ... MUST WATCH Assad performs Eid prayers 01:01

JUST WATCHED Annan: 'I cry everyday for the Syrians' Replay More Videos ... MUST WATCH Annan: 'I cry everyday for the Syrians' 02:39

Omar found his brother in the makeshift field clinic, in the basement of the town's mosque.

"Once he saw me, he shouted 'Omar!' -- shouted with all his strength. I didn't see what happened, I just saw blood. When I got closer I saw his leg and I just yelled and I started crying."

Abdulrahman's leg was amputated; there was no way to save it. It was practically entirely severed just below the knee.

"After he woke up I was crying, I couldn't control myself, and he said, 'If you love me don't cry,'" Omar recalls, eyes slightly widening, acknowledging our amazement at his brother's strength. He says Abdulrahman made him promise not to cry in front of their mother.

"I said I will control myself," Omar continues. "I told him, do you know where your leg is? He said, 'I know it's cut, I keep feeling it, it hurts.' I told him it just went before you to heaven."

And that is also when Omar made another promise to his younger brother: that he would walk again.

Omar started working to save money for a prosthetic, but quickly realized that it would take too long to raise the funds. He began asking around, went online. A group of Egyptian doctors happened to be visiting the field clinic, and they told him about the Global Medical Relief Fund , a small U.S. nongovernmental organization that is dedicated to helping children badly wounded in disasters and war zones. GMRF takes care of children's follow-up prosthetics and physical therapy until they reach the age of 21.

The founder, Elissa Montanti, quickly responded: Yes, of course, she would take on his case, but first the brothers had to get to Turkey.

They did make it safely across the border. And after a long and arduous journey navigating a country they don't know, a language they don't speak and with meager funds, they made it to Ankara, the Turkish capital, where they are now waiting.

Montanti has been working on the brothers' paperwork to get Abdulrahman to the U.S. for medical treatment, made all the more challenging because they don't have passports.

Their visa requests were denied. Now they are waiting to see if the State Department will grant them humanitarian parole.

Omar pulls his brother in closer, gently stroking his cheek. The two, always close, are now inseparable.

But Abdulrahman, despite his frequent shy smiles, is constantly plagued by the memories.

"He has nightmares and sometimes daydreams, bad daydreams," Omar tells us. "He says 'I feel it, I feel just like there is a snake around.' I keep telling him it doesn't exist and he says it hurts and starts screaming."

Abdulrahman, under his breath, says he sees a big one, surrounded by smaller ones.

Omar says his mind is always churning, obsessed with make sure his brother is, quite simply, OK.

"All the time I think how to make him comfortable. It's just like raising a child -- I have to take all the responsibilities. He needs to be educated again. I want to take advantage of this situation to teach him languages, everything I can."

Tragically, Abdulrahman has already learned one of the harshest lessons of all.

"The most important thing that he's learning at this time," Omar says, "it's to be aware, to grow up his mind. He's not a child anymore."