Georgie Christine is back in the UK after 32 years, having worked the last 17 with pre-school children in the shanty towns of Brazil.
She told me about Paulo, whom she'd met 16 years ago.
"When [husband] Stuart and I first met Paulo, he was living in a hovel in the shanty town of Jardim Olinda - part of Sao Paulo's sprawl. Where he lived was so bad, I wouldn't have put my dog there," she said. "There were rats everywhere. He had a wife and 14 children but was continually drunk and gambling.
"We were church planting in Jardim Olinda in those days, and were seeing a lot of conversions. We used to have Bible studies in people's homes. If Paulo was around, when we came in the house, he'd run out the back door.
"Then one day he stayed at the Bible study and soon after was converted. And Paulo says of that day, 'that was the day my life began'." At that time he was 62 years old.
The change in Paulo was immediate and hugely visible. He got a job and stopped drinking, smoking and gambling. Paulo started to take an interest in where he was living - he did the house up - and began to take care of his wife and children.
After six years he decided to leave the shanty town. "He'd saved up - how, I don't know," said Georgie. "He bought a little plot of land, built some houses on it, and got his family to move out of the shanty town." All his family became Christians, one by one: his wife, his children and his grandchildren.
"He says he's lived most of his life since he was 62," she added.
Georgie can't contain the emotion she feels when she thinks about Paulo. "He'd lived with the mud and the rats all that time until Stuart arrived," she said. "And now he actually looks younger. It was a privilege to see someone's whole life change in that way, not just in a spiritual way but every aspect of his life had been changed by God. And his family too, including his grandchildren - who'd been my PEPE [pre-school] children." She paused, thinking about the way this man's life has changed since he became a Christian.
"Visiting him in his new home must be like going to heaven!
Just before Georgie and Stuart left Brazil, they were invited to visit Paulo. "It was quite an emotional visit," said Georgie. "It was amazing to see him living in a really nice house with a view, and lots of his family living nearby in the same street."
When Stuart saw him, he said, "Visiting him in his new home must be like going to heaven!"
Jan Webb is BMS World Mission's Editorial Co-ordinator