"Give it 10 years," he said then. "In the year 2000, I believe we will be back in world cricket, beating the best." It was a prophecy which raced to fulfilment; a little more than two years later, at the age of 40, Henry would become the first black man to play Test cricket for South Africa for nearly a hundred years.
At the time of his pronouncement, Henry was player/coach of the Scotland team, spending the best part of a decade here turning out for Poloc, Stenhousemuir, West Lothian and Arbroath. Gavin Hamilton, the former Saltires captain, is just one of our successful own who credits Henry's nous for much of what he achieved - a defining trip was arranged for the youngster to go to South Africa to experience foreign conditions. "He shaped my whole career in a matter of weeks," Hamilton admitted.
The early stages of Henry's own odyssey were forged, in more ways than one, by Basil D'Oliveira, another non-white who, decades earlier, had broken loose of his nation to seek his cricketing fortune on more tolerant shores. His attempt to return - in 1968 with an English touring party - was blocked by South African authorities, the impetus for the sporting boycott which excluded his compatriots from the world stage.
Henry, a young, black, sports-mad schoolboy, was to come into more tangible contact with a kindred spirit. "There was a seed planted by D'Oliveira," he admits. "He came out to coach at my school and that's when he told my parents he wanted to take me to England. They said no way, they weren't going to take the risk, to let me go. But once that seed was planted that was where I wanted to go."
It was a seed that took a decade to flower; Henry made the journey to England at age 24, setting himself up in Manchester, before being tempted north for a trial at Poloc on the behest of businessman Don Haines. His two showcase matches were - typically - rained off mostly, but Haines had already seen enough to offer him the chance of being the club's professional. It was a years-long experience that shaped his life: his children, at times, still have traces of a Scottish accent.
"I miss the people, the characters," he admits, speaking from his home in South Africa. "They were very passionate about their country, about their identity. I really learned an enormous amount from the Scottish people. What I do appreciate is the opportunity they gave me."
A greater gift, though, was the platform to show off his skills, one which led to home call-ups for the late-1980s rebel tours which offered South Africa a strained glimpse at the rewards an end to apartheid could hold. Some railed against his decision to break the boycott - he was branded a sell-out, an 'Uncle Tom' - but while Nelson Mandela was striding the political spectrum, Henry was imposing himself as a sporting symbol of acceptance and reconciliation.
He was fiercely competitive, too: what sense in returning with no experience of playing the game at the highest level? If South Africa were to make an anticipated comeback, it could only be made in style. "There were a lot of people against my approach, how I went about my whole career," he admits. "It was a complex and threatening situation. My family was threatened, because I was labelled at times as a sell-out. They would make remarks, make phone calls; newspapers would write about it. I had to learn quickly how to manage those situations."
Then, it changed. Mandela was freed, the country was transformed. The ICC began shifting the pieces that would lead to South Africa's return to the world stage. Henry could sense it was coming, with the World Cup in 1992 - only lost in the end, some would argue, because of a senseless rain delay recalculation against England - the light at the end of a long tunnel.
"It wasn't a surprise," he concedes. "The rebel tours came, the ANC - who were then underground - got involved; the cricket organisation started to approach the re-entry into world cricket, the release of Nelson Mandela . . . they carved a path. It was all done in the background, as cricketers we knew something was going on although we didn't have the details at the time."
By this time, Henry was in his late 30s, and competition for the spinner's place in the reborn Test side was fierce. He took a risk, leaving Scotland to play for Orange Free State - with a young Allan Donald and Hansie Cronje - and snatch at one, last desperate chance. But despite his advancing years, he was in the form of his life with bat and ball: the call-up came.
"It was something I never thought could happen, going to represent South Africa," said Henry, who was 40 when he faced India in his first Test. "When I decided to play, the ambition was just to have a career.
"I realised I would get looked upon as a pioneer, opening doors for some people or laying down foundations for others. And although at times it was very difficult, I think I came out unscathed without many mental scars. I don't think there are [any regrets]. Even if I lived in a country with equal opportunities . . . what I've gained now could never compare with anything else."
It is an extraordinary tale of a man who, at an age in which such things are usually wispy flights of middle-aged fancy, finally achieved that which he had thought would always be beyond him. Henry is, of course, one of many who owe a debt to Mandela, as a man who fought the same battle on a different, oval field and emerged equally triumphant.
Henry's reverence of the statesman manifests itself clearly; he all too often slips into the present tense in reminiscence. "I met him when we played India for the first time; he came and shook hands with the team . . ." Henry trails off, lost for a moment. "He was a remarkable man. When he is in your company, everything changes. When he talks, nine times out of 10 there's wisdom there. He does his homework about you, as well, he knows who you are and things about you. There was an aura about him."
Nelson Mandela was out at 95, just five short of what traditionally marks a significant contribution in cricket. Some legacies, though, and especially this one, transcend all conventional milestones. "There are so many today who benefited from his sacrifice," says Henry. "His presence changed an environment."