I believe the person is taking that extra month off /in addition/ to taking the standard PTO. (Which is around 3-5 weeks with holidays at FAANG)

Perhaps very few make that year after year, but that's a totally achievable total compensation anywhere in the top half of the individual-contributor range if they get two good evals in one year. I work at one of those companies, and I'm sure I talk every day with people who have hit that level at least once.