Some of the happiest and most satisfied people I know are academics who work 80+ hours a week because they love what they do. You don't need to sacrifice health to work more than 50 hours a week. And realistically there is no long term health damage from what he is doing. And yes you can trade money for better health, though in the first world you rapidly hit diminishing returns but if your sleep deprivation can make the difference between being able to afford good health care or moving to an area with less pollution it absolutely can trade off like that.
I don't believe you.
Even if they told me themselves I wouldn't believe them.
Even if they were beaming with joy as the black circles in their eyes squinted while swearing there is no better joy than that of labour I would do what one of my ex-employers did and turn off machinery at 17.00 sharp.
There is no happiness in working long hours; there must be no happiness. Happiness must be verboten for anyone who thinks that undermining organized labour gains is "loving what they do".
If you make B2B SASS, and you love your work, there's something wrong with you.