We had a great stay at Katalin's place. Although the building is older (to be expected in Europe) it is updated. The bed is good and clean towels and essentials are provided.
This is home has multiple Airbnb rooms, I believe there are 3. There are 2 bathrooms which are shared. There is a kitchen provided, which is also clean and nice. Unfortunately, we didn't get to use it because we were too busy touring.
There are many stairs to climb to reach this room. Just be aware in case you have large luggage. It is quite a workout.
There is also a caretaker who will likely be the person to check you in, named Federico. We did happen to meet Katalin as we were heading out.
Overall, a nice place to stay while in Brussels.