And if he decided not to do it, no one would mind. I say this as someone who has worked (briefly) in ICU, as well as having volunteered in a hospital school for two years, and (unfortunately) have had my own teenager in the ICU.
The difference we are talking about with work is that a person gets paid if they do work, and doesn't get paid if they don't.
When someone is unwell enough to be placed in an ICU, it is important not to be flippant about suggesting they do things for money. Even putting aside the ethics of it, or the fact that in some caees additional burdens could literally kill them, if you get your worker to give your company an extra few thousand dollars value and that worker ends up taking an extra day in the ICU, how much do you imagine that extra day of ICU treatment costs? And what sort of other costs might there be that aren't captured in dollars?