People throwing around profit margins from 2018/19 are missing the boat on this. The key metric is how much cash the club actually has on hand as of April 1 2020.
Using some recently released figures, Spurs had 123.5 million in cash on hand on June 30, 2019 (all figures are in GBP). That number is surely lower as of April 1, 2020 after the purchases of Ndombele, Sessegnon, Clarke and Lo Celso, as well as increased wage expenses for players and additional staff required for the new stadium. The club also only received about 75-80% of expected revenue the 2019/20 season.
Total expenses were 292.4m for 2018/19, so between that and the interest on club debt, outgoing monthly cash is, at minimum, 27m. Now those expenses will go down for various reasons (expenses related to match days, travel, training, etc..) but a lot of these are high fixed cost (player salary, for instance). If I had to guess, the club likely has enough cash on hand to sustain operations for a few months to half a year at most.
Again, I think the club should be making the furloughed employees whole and pay the 20% on top of the 80% provided by the government scheme, but the numbers make it clearer as to why Levy is rightfully concerned about the club finances given the uncertainty at the moment. Football clubs are relatively small operations and basically have no margins in the long run. Most clubs rely on their owner to cover the difference especially in times like these, and ideally, Joe Lewis would sell a painting or two and we wouldn't even be talking about this, but for the moment Spurs are on their own.