There was a time when Reda and his nine brothers looked forward to going to war. From the house they had turned into a base in Aleppo’s southern suburbs, they would load up the truck most days and drive to the frontlines just beyond the city limits to take the fight to Bashar al-Assad’s forces.

Things were simpler then. The 10 brothers in arms knew their friends and their enemies. Now, none of them are sure of much anymore – except that the cause to which they devoted themselves is dying a slow death.

“Nothing can save it,” said Reda, the youngest of the brothers, now a refugee in Germany. “And no one wants to help anyway. When the Russians started bombing, it became more serious than before.”

In early 2013, the Guardian showcased the brothers, who were then the causes célèbres of the rebel groups in the eastern half of Aleppo, held by those trying to force the Syrian leader’s removal.

Like nearly all the opposition fighters in the county’s second city, they were men from the countryside who had flooded in eight months earlier when regime control, which had been resolute for decades, started to crumble.

Aleppo had always seemed distant to them, a hub of establishment money and power that had remained far from the reach of the rural poor. But insurrection had sparked an opportunity to change that and the brothers soon left their lives in the town of Sarmada, near Idlib, in search of weapons and backers.

When they reached the city, they dug in alongside other rebel groups, among an unfamiliar urban landscape, each staking a claim in neighbourhoods emptied of people, some of whom had left cooking pots on stovetops and laundry hanging on racks.

When nine of the brothers posed with their weapons in February of that year, excitement was palpable.

They had secured the weapons they were looking for and had quickly become a spoke in an umbrella organisation of rebel groups who had pinned down the Syrian army and paved the way for a push they believed would oust Assad and lead to a recalibration of power in Syria – the culmination of a popular current first evident on the streets of Deraa in early 2011.

Five years since the beginning of the uprisings that ignited the war, only three of the brothers are still fighting. One has been killed (he was holding the rocket-propelled grenade in the portrait). Two more are working at medical centres in Aleppo, and the rest, like Reda, have faded away.

Disillusionment crept in slowly, he said, and had a number of factors. It started with the realisation that frontlines, which had appeared brittle and dynamic early in 2013, had become stagnant later that year.

By then, jihadis who had been slowly gathering strength in the second half of 2012 had also moved into eastern Aleppo, first the al-Qaida-aligned al-Nusra Front, and then an even more visceral, uncompromising group – Islamic state. Their presence complicated a cause that until then had little to do with broader ideological or regional grievances.

“But we could avoid them,” Reda said. “The big problem was in late 2013, and the beginning of 2014, when a guy joined our group. We trusted him, but he was a regime spy and he stole all the weapons and money. We had about 15 Kalashnikovs and a machine gun. We went to al-Tawheed [a coordinating arm of Aleppo rebels] and they did nothing. They abandoned us.”

Worse was to come. In 2014, a rival group arrested four of the brothers. “There was me, Anas, Rafat and Ahmed who weren’t there. They took the remaining guns we used to protect ourselves, and then locked the others in a house.

“They were going to do something, maybe kill us. But they realised we were from Idlib and we had a lot of cousins who would come for them. They knew we were good people, but the only way to save face was to take us to a court. They said my brothers belonged to the regime. They put them in jail for one month and they had to pay to get out.

“We have a lot of enemies, I swear. We fought Bashar al-Assad because he did this sort of thing and now they are doing the same.”

Rafat, who remains in Aleppo, said he, too, was losing hope that the war’s goals, as his family had envisaged them, could ever be achieved. “It is very difficult now,” he said. “Especially since the Russians arrived.”

The brothers’ neighbourhood, al-Fardous, lies in ruins after two years of intensive bombing, first by the Syrian regime, which obliterated much of the rebel-held east with barrel bombs dropped from helicopters, and lately by Russia, whose month-long blitz ahead of a current partial ceasefire, turned still-standing ruins into jagged rubble.

For Reda, the decision to leave came quickly. “One night I came home and we found a letter hammered into my door with a threat from al-Qaida,” he said. “Then it became serious. Rafat was there 15 minutes before and didn’t notice anything. My father said we had already lost Anas and he didn’t want to lose anyone else, so I left for Turkey that night.

“I never fought alongside them. I was an activist and I carried a weapon sometimes for protection only.”

His journey took him through Istanbul, a Bulgarian jail, and then to Germany where he is trying to decompress and become established almost 18 months on.

“I still speak to my family most days,” he said. “They feel like me. We are not going to protest the revolution again. We are going in the wrong direction.”

Although diminished, the brothers’ unit still exists. Other rebel groups also remain dug into what remains of Aleppo.

But outside the city, the fate of which has come to define the battle for Syria itself, the view is foreboding. About 15 miles to the east of the remaining groups, Isis has moved in. Hezbollah, Iraqi militias, some elements of the Syrian army and Kurdish forces allied to them, have taken a blocking position to the north, all but besieging the city and severing the escape route to Turkey.

“Everybody is fighting for Syria now,” said Reda. “Everyone except those who were fighting first.”