Chad Le Clos has booked his butterfly spots, but not yet in the 200m freestyle, where he won Olympic silver at Rio 2016.
So far only 13 South African athletes and six swimmers have qualified in individual events for Tokyo, with several others in both codes on the fringes, including Erin Gallagher, who trains under Hill.
Just one of Barrow's three rowing crews have qualified to date.
In all, only 53% of athletes across all Olympic codes worldwide have qualified.
Barrow's rowers have been in camp at Katse Dam in Lesotho, pumping out good performances, spearheaded by 2016 Rio silver medallist Lawrence Brittain.
"Lawrence has had the best six months of his life," said Barrow. "He's in better shape than he was before Rio."
One potential partner, Kyle Schoonbee, broke the SA ergo record shortly before the camp started, giving Barrow the potential to field SA's strongest men's pair yet.
"We've been very fortunate, but the rest of the world, especially Europe, have not been ... We know people in Italy and that country is in devastation."
Barrow said it was possible his rowers might have to train in isolation at home after they return from camp in a week or so.
Hill said his swimmers were taking a break now - as opposed to the break they would have taken after the SA championships that had to be postponed - in the faint hope the situation normalised by President Cyril Ramaphosa's April 14 deadline.
But he expects the pandemic to last longer than that, given the cancellation of sporting events in late May, like the Monaco F1 Grand Prix. "I don't know how they think, six weeks after the Monaco GP, we're going to be ready for the Games. How do you prepare for the Olympics?"
Hill pointed out that athletes had just three months left to train properly for Tokyo, from April to June.
"If we're under pressure for two of those three months, it's impossible."
It remains to be seen how long the International Olympic Committee (IOC) can resist the now quickly growing calls for a postponement, with even the coaches of retired greats Usain Bolt and Michael Phelps - Glen Mills and Bob Bowman - joining the chorus.