Sarah Brown is starting to think that generosity is contagious.

Last year, when an Aboriginal corporation donated a $90,000 Albert Namatjira painting to help pay nurses for delivering remote dialysis services, the chief executive of the Purple House dialysis clinic in Alice Springs declared it was the only such phone call she was likely to get.

She was wrong. A man in New South Wales who saw the Guardian Australia story rang to say: “You don’t know me, but this is your next phone call like that.”

He had a Namatjira watercolour, which had been hanging on his parents’ lounge room wall for the past 60 years, and he wanted Purple House to have it. He and his mates from the local men’s shed had even built a special crate in which to ship it.

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The painting arrived late last year, and Brown stashed it down the side of her desk in the hallway of the cheerfully chaotic Purple House while she figured out what to do with it.

Last week, an Aboriginal corporation in Alice Springs bought it for $18,500 then donated it to the public collection of the Araluen Art Centre.

“This is such a lovely story of somebody deciding to help us out, but in the process central Australia gets an Albert Namatjira back, and everyone will get to see it,” Brown said.

“That money will go into helping get more people back to country and to help them suck the juice out of every day that they’ve got left, and make sure they’ve got time to spend with their kids and grandkids and pass on their cultural heritage.”

Purple House provides lifesaving dialysis to Indigenous patients in Alice Springs and a number of remote community clinics, and operates a travelling clinic, the Purple Truck.

Facebook Twitter Pinterest ‘A huge thank you for this enormous gift.’ Purple House CEO Sarah Brown. Photograph: Anna Cadden/The Guardian

This most recent benefactor wanted to remain anonymous. He died last month, but according to Brown, his family said he was “really proud” he’d been able to help.

“We are sending our love to them and a huge thank you for this enormous gift. I don’t think he was a particularly rich man and it was a significant, heartfelt contribution of something that could have remained in his family,” Brown said.

The federal government recently added remote dialysis services to the medical benefits scheme, which Brown said is a “game changer”. From November, Medicare will cover some of the costs of dialysis, which are roughly $590 per treatment.

Until now, Purple House has provided care thanks to fundraising and private donations. It is about to build the first South Australian dialysis unit at Pukatja (Ernabella), with others planned for Utopia and Kalkaringi over the next six months. Brown has met with groups from the Pilbara and meetings are scheduled in Coober Pedy and Cairns.

“Purple House can’t be everywhere – and we shouldn’t be – but we want to help other Aboriginal groups get their heads around what it takes to do dialysis out bush and be a support for those communities,” Brown said.

“We know how hard it is for people to be away from their country, and we know how hard it is to start dialysis from scratch. They can learn from all the things we’ve learned and all the mistakes we’ve made, and we can help grow some other services up.”

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Purple House now has a four-year funding agreement with the federal government, and some respite from needing to “beg, borrow and steal” to keep the service going.

Nevertheless, Brown said, they will keep telling the story about why going home for treatment is so important.

“Think what it would be like to be a traditional Aboriginal person from a very remote community who suddenly gets told their kidneys are buggered and they have to leave everything they know and love to be close to hospital,” she said.

“What’s in danger of being lost when they don’t have a chance to pass on their cultural heritage to their kids and grandkids? It’s a loss to their families and communities, but it’s a loss to all Australians. A whole lot of knowledge about looking after this place – that is only in the heads of those old people.”