I've noticed this too, and it's not just about comparison with US - the relative salary compared to other jobs in Germany seems to be exceptionally low, from what I hear. I wonder what causes this anomaly?
Compared to the US, you will not find many rich people in Germany. At the same time you will also not find many poor people. Generally, people are quite equal in Germany.
No one is saying there isn't eng. talent in Germany. They're just mistreated by the system.
And the valley tech giants know this very well and take advantage of it.
I assume that the brother from your anecdote doesn't declare all his income (you are left with about 60% of your paycheck after taxes and mandatory insurances). I don't see how a programmer salary isn't enough for two people to make ends meet.