The location of this apartment is the real star of the show. It's in such a wonderful spot with easy walking access to the downtown area of Lisbon, as well as to public transport elsewhere. The apartment is compact but comfortable. The shower is powerful (something I always look for!) and the small terrace is a lovely little spot (albeit not one we made huge use of).
Things to be aware of: the apartment is up four flights of fairly steep, narrow, wooden stairs. This didn't present a problem for us (it gave us a little workout!) but for less able travellers it might be problematic. Also, we were visiting in very hot season and the a/c wasn't effective at cooling either of the bedrooms we used. I typically sleep in a cool room so this was tricky, so be aware of it!
All in all, Hugo's apartment is a fantastic base to explore Lisbon and he and his family who we had contact with were friendly and helpful the whole time!