Jonathan's apartment is perfectly situated.
It itersects two, more or less, straight paths to the station (Brussels Midi - where you'll get dropped off if you take the coach from Charleroi Airport) and city centre. It's less than a 20 minute walk from Brussels Midi Station and about 25 minutes to to centre. It's also right next to a metro stop if you don't fancy the walk!
We had a great time exploring Brussels over our weekend, Jonathan was very welcoming and the bed was so comfortable it was a joy to sleep in after long days of walking around the city! Would definitely recommend.