King Amannullah’s palace must have been a splendid sight when it was built, back in the 1920s. It’s a bombed-out shell now. Just a short walk away there’s a squatters’ camp called Ruas-e-panj.

About a dozen families live there, in a collection of crumbling stables, and we’d come there to share a meal of apples with Nasir Ahmed. At 16, Nasir had the face of an old man, but he was the size of a five-year-old. He was dying of tuberculosis and polio.

I was visiting Nasir with Mahboob Shah, a tireless, 38 -year-old Kabuli who spends his days driving around in a rickety old Korean bucket-of-bolts, visiting squatters’ camps and writing down their particulars in a little green notebook.

Mahboob nodded to two urchins, in rags. “Those two children, sitting there. They can no longer walk.” He nodded towards a little boy. “This one is Ramin, Nasir’s youngest brother. His legs don’t move anymore either. When I first came here, there were 12 young children and they could not stand. There was one who was seven years old. He weighed four kilograms.”

Malnutrition, vitamin deficiency, tuberculosis, polio, no school, many widows, no work – these words appear quite a lot in Mahboob’s notebook.

Mahboob’s job is to visit Kabul’s homeless encampments, determine their most pressing needs, and try to hook them up with help from his contacts in Kabul’s anti-poverty agencies and international charities. He more or less invented the job himself, but lately he’s been getting a small salary for it from a non-governmental organization he cannot name for fear of reprisals from the Taliban.

Mahboob does this work to treat an ailment of his own. “I have a kind of mind problem,” he said. “It only feels better if I am finding something to do for these people. If I can’t, I always wake up in the middle of the night. It is like they are my own children, my own brothers and sisters. All the refugees in Kabul know me, I think.”

Then he laughs at himself, pointing out that depending on how you define the term, as many as half the city’s nearly five million people could be considered homeless refugees. They live in cellars, alleys, tent encampments, hastily-built mud houses, and bombed-out buildings.

On our rambles through Kabul, Mahboob pointed out some of his haunts. Here, a complex of half-collapsed buildings left over from the mujahedeen wars, behind the Russian embassy. Maybe 50 families. There, near the opulent mosque-and-madrassa complex run by the hard-line Tehran-backed cleric Mohammed Asif Mohseni, another encampment about the same size. “And there.” Mahboob points to a warren of canvas hovels along a busy thoroughfare. “That is a new one.”

It’s the small stuff that works, Mahboob said. In Kabul, a little bit of money can go a long way. For $1,000, you can run a tent school for 200 kids for a whole year. One hot water bottle can keep a child from dying in the winter. Give an unemployed man $5 worth of fruit, vegetables and hand-me-down clothes in a pushcart, and from that he can build his own enterprise.

From the cast-off intravenous bags and tubes from local hospitals, Mahboob helped a small, independent charity develop a hydroponic gardening system for a destitute neighbourhood on a hardscrabble city hillside. The left-over shipping pallets from the sprawling U.S. base at Camp Eggars provided a fortune in construction material.

Every day, Mahboob rises at dawn, says goodbye to his wife Waghma and his infant sons Sharem and Pashan, and goes for a long run. Then his working day starts, with his notebook and his rickety Kia, “the dustiest car in Kabul.” Every day he encounters sorrows like Nasir Ahmed.

“I become sad, yes. But when I find someone who is very poor, I feel very happy to help them stand on their own feet. So I just stop thinking about these things. I just do what I can do.”