You can throw all the money you like at a problem, but without trust, it is nothing. Sounding brass, tinkling cymbal: worthless. The people you wish to help must trust the process, and they must trust the organisation. And all of that comes down to trust between one person and another.

That’s not always a rapid process. But there was John Kaseenchi, a man that Agnes and Bernard and their sixth child all trust – now – and he was roaring across the bumps and hollows of a wild road deep in Masai territory, mounted on a motorbike tough enough for the challenge. Kaseenchi, in his biker’s gear and his helmet, was making a delivery of trust. It’s routine now. But it was a long time in coming. Nothing to do with Aids is simple; we are not in quick-fix territory.

Agnes and Bernard are not their real names, just popular names among the Masai, but AID Village Clinics takes a strong line on patient confidentiality. Part of the trust business: but the couple were happy to be photographed. And there they were, the three of them, coming out from their hut at the sound of the motorcycle, looking a million dollars, as only the Masai can: tall, both more than six foot, stately, wearing the traditional scarlet robes, Agnes lavishly beaded, Bernard wearing a woolly hat with a Mercedes-Benz logo.

We followed less stylishly (and much less efficiently) in a 4x4, to find this stately couple looking like monarchs. They are anything but, in truth, and have come through dark and very long times. It seems hard to believe: they look as if they had been set up to provide a model of rural content.

Bernard first went to the clinic at Mbirikani five years ago, and was found to be HIV-positive. His response was to keep it quiet, especially from his wife, and then to decamp to Nairobi. He found work as a security guard, a natural occupation for a Masai, and simply disappeared.

But he came back the next year, feeling rotten, full of aches and pains and fever. Eventually, a year later, he consented to treatment again. He now had a heavy viral load, and was doing very poorly. He kept up with his treatment for three months, and then disappeared again.

With strange inevitability, he came back after another year. He found that his baby was ill – the other children are grown up and living away from home – and his wife was ill as well. The child had malaria and pneumonia. But still Bernard resisted. And so the child got worse and life got pretty desperate. At last, Bernard faced up to it. He told his wife. She and the child were tested; both are HIV-positive. The whole family began to take treatment. After that, it was a matter of counselling: with the right drugs, proper nutrition, clean water and a good attitude, HIV-positive people can live for years.

Agnes and Bernard embraced that concept: and they did so because of Kaseenchi. They did so because a man they trusted was able to come out to their very remote place and talk to them. Drugs and dietary supplements from the clinic have turned things around: the better your diet, the more resistant you are to infection.

“I was very weak,” Bernard said. “How could I travel to get treatment? I could not afford the bus fare. I have only two cows.”

“And how many times can you sell two cows?” Kaseenchi asked.

The child weighed 9kg at 2, which is dreadful, and 20kg at 4: quantifiable improvement. “Aah!” he said, when requested, as he went through a routine check-up. He is now well accustomed to the routine of sickness: for without routine, the condition will win. And it is not winning.

“I have never been to school,” said Agnes, before showing us what she has learnt from Kaseenchi. How she draws 7.5ml from a bottle before giving it to the child, how she copes with basic hygiene, how she stores the medicines safely. “It’s a very complicated thing,” Kaseenchi said. “I can’t be there morning and evening. I have to train them.”