Source on this? Been living in Spain for 8 years now, and my wifes family have a number of empty of apartments here. AFAIK, they do not pay tax on any of them for being empty.
IMO that is one of things they can do to address the housing issue we have but I have seen no mention of this policy anywhere.
My wife grandfather bought them as an investment and after he died, the grandmother inherited them. She couldn’t care less about them as investments, but I guess my in laws are waiting to inherit them and then sell them off.
This pedantic objection is silly. First of all, nobody (well, no adult) is going to think that free means that it didn't cost anything -- there is no manipulation going on. But secondly, I would argue that the word doesn't mean what you are implying. If a bar offers you a free beer, would you also object that it was in fact paid for by someone? What would ever be "free", by your definition? Weather?