With a PhD in physics or astrophysics, they'll make between 60k and 200k a year (usually less than 100k). It's a job you do because you love it, not because it will make you rich - medicine would do that in a lot less time. But hopefully your friend is willing to move around a lot - there aren't a ton of jobs out there for astronomers, so we have to take what we can get, even if it involves moving across (or out of) the country.
