Argh. We all have these stories of lost hours because of an assumption that proved to be wrong. Nowadays, whenever I help someone debug an issue, I insist on starting from zero assumptions (by making self depricating jokes, and stating that I need to understand the context properly). Furthermore, the culture/way of communicating in German might a _lot_ more direct and interpretable as negative than in Brazil. I'm Dut…
However, we also need to keep in mind the possibility that he/she is working with negative people, that are simply a*holes. If that is the case, I'd recommend looking for a new team.
I'm also an immigrant in Germany and so far my experience has been positive on most teams, so if someone feels that a team is hostile, negative, belittling, don't stay there too long only because "I must be too sensitive and I can't handle how Germans communicate". It's not always your fault.