Mohammad is a very kind person and gave us a handful of tips for what to see and where to eat in Berlin. We were quite surprised that he was staying in the apartment with us all the time - it was not clear from the advertisement, but in the end it didn't bother us (besides the fact that we were told to keep our mask on ALL THE TIME when we are in the apartment - we were both vaccinated and it was neither necessary nor comfortable).
On the other hand, what did bother us, was the smell in the apartment. It is very old apartment and it does not smell good. The fridge was even worse - it was full of food and mixed meat and vegetables without the lid on, I guess it had been sitting there for more than a week, because the smell was unbearable. We rather did not keep our food there.