re: Home in Belgium tax question

My sister married a developer there. He is building in the museum area of Antwerp and offered to sell us a unit at cost. My father and mother will use it to visit. Sister can manage it for me. I expect the property to appreciate significantly as there is a huge park being built across the street and it’s a prime location. Planning on 28 day minimum AirBnB rentals when not in use. Met a guy there who does this there and says he is always booked.

Didn’t want to give a huge story but a lot of people seem to be focused more on why I would buy instead of my original question of what are potential tax issues. Taxes is my main question.