For what it’s worth, and not exactly comparable, I lived in Germany for 6months in my late 20s, so a long time ago. I was working and spoke reasonable but not exceptionally good German. It wasn’t always easy to navigate social situations even at that age, and would not have liked to be ill or in difficulties there, though to be fair, all the professionals spoke excellent English to the extent that I struggled to practice my German as they wanted to practice English on me. I found it quite an isolating experience, but then, I had no family nearby. People were very friendly on the whole. But officialdom was a nightmare, very rigid and dictatorial, and of course different to what I was used to in the UK. Austria might be a bit more relaxed. But I have to say, I wouldn’t do it now. In your 20s, fools rush in, etc,etc.
In the end, only the person affected will be able to decide. But I quite appreciate why they would want to canvas opinion and experiences widely.
I always wonder, with this type of post, if “asking for a friend” masks a personal query?