I won't say that's not a valid choice (I've seen it done) but if it comes down to that, the tarnished reputation is probably going to hurt them more than the money they get. This industry is not all that large at the FAANG level and the people who succeed or at least do moderately well at a FAANG tend to go on to senior positions at other companies. This person probably does not want a bunch of former co-workers around to say "Oh, that person; I remember them. A nice enough individual, I suppose, but no hire."
On top of that, the wash out process isn't likely to be all that pleasant, particularly if this person has depression problems already. Getting negative feedback and the cold shoulder from their colleagues for months/years is probably very demoralizing even if they are still drawing a big paycheck.
