Monica Costa Riba is a migration campaigner for Amnesty International. The views expressed in this article are those of the author.

(CNN) Strapped onto either side of a horse, 30-year-old Alan Mohammad and his 28-year-old sister Gyan crossed craggy mountains from Iraq into Turkey.

Their younger sister walked ahead, leading the horse. Their mother, brother and another younger sister trailed behind, pushing heavy wheelchairs up the steep, unpaved path.

Alan and Gyan, both teachers, have suffered from muscular dystrophy since birth. Mobility has never been easy. But as ISIS attacks rocked their home in Al-Hasakah, in northeastern Syria, the family knew it was time to move.

But where could they go?

I first met Alan in July in Ritsona refugee camp, about 50 miles from Athens.

"It was a very difficult journey," he told me. "For 'normal people' it is very difficult. But for disabled people it is like a miracle, because all the borders between the two countries [Iraq and Turkey] are mountains."

They tried to cross into Turkey from Syria three times. Each time, they said, they were fired on by Turkish police. So they tried a different escape route, into Iraq, where they would stay for a year and a half, until the approach of ISIS made it necessary for them to flee again.

So once more, they set off for Turkey.

Alan and Gyan

The family managed to contact a people smuggler and paid $750 each for passage to Greece. The smugglers assured them, they recounted, that there would be around 30 people traveling in a boat that would be 9 meters long.

When they arrived on the beach, they found an inflatable boat only 6 meters long, and 60 people clamoring to get on board. The smugglers told Alan and Gyan that there would be no space for their wheelchairs.

"It was terrifying. We were in the water for around four hours," recalls Alan. "Every time I looked around I saw babies and children crying... My mother became faint and at one point my sister told me she could not go on any more."

They were finally rescued by the Greek coast guard and taken to the island of Chios, where Alan and Gyan were given wheelchairs.

They arrived on the island on March 12, just days before a deal between the EU and Turkey aimed at stemming the flow of refugees came into effect. The borders of other European countries were now closed to them.

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Any hopes that they might be permitted to join their father in Germany, where he had managed to travel ahead with another sister, were dashed. An appointment with the European Asylum Support Office to discuss family reunification failed to materialize. Instead, the family was made to board a ferry to the mainland, where they were taken by bus to Ritsona refugee camp.

Ritsona is an isolated open camp on an abandoned military base, in the middle of a forest. Physical conditions there are challenging, with sweltering temperatures during the day. The food provided is so poor that much of it gets thrown away, attracting wild boars. The sandy ground and protruding tree roots make it particularly hard for Alan and Gyan to get around, and with winter approaching, conditions are set to get much worse.

Alan remains positive. He teaches English in a makeshift tented classroom provided by NGOs. The children's cheerful enthusiasm contrasts starkly with the miserable conditions of the camp.

The closure of the so-called Balkan route into northern Europe, and the failure of European leaders to resettle and relocate refugees, has left almost 60,000 refugees and migrants stranded in Greece. They live in a state of constant fear and uncertainty. It has also meant that Alan and his family will remain separated from their father and younger sister.

But Alan remains hopeful that things will change.

"Here we have doctors and teachers. We left our country because of the war," he says. "I want to say to the European people that want to welcome refugees, thank you. And to the others, don't be afraid."