Vacant Apartment Complexes? and why unlisted?

[Brooks F.]

I've seen some vacant apartment complexes, and it always confused me. I've now been presented an opportunity to buy a medium-large (44 unit) apartment complex... that is vacant. The numbers add up pretty easily- the area is rentable, fair rents, building seems decent. 

Now my problem is I don't understand WHY a complex would be vacant, void of major repairs. In this case however, while it could use some updates, the seller claims its fine . The weird thing though is the guy is really old (close to 80), and he has 11 complexes he's selling. 4 are vacant, and the other 7 are 20-60% capacity. There are no listings at the places that are even partially at capacity.

I did a little due diligence- there's nothing weird filed with the govt, no back taxes, no notices of it being uninhabitable.... just vacant.

I also don't understand why you wouldn't put a property like this formally on the market. I get unlisted apartment complexes with people in it, because you don't want them to know its for sale, but vacant?

I'm about to walk away just because the whole thing sounds "fishy", but I have read about people buying "vacant" apartment complexes when I search here. I love the idea of buying a complex like this, but it just doesn't add up. Can anyone on here weigh in? is it worth having someone inspect it? Help me understand!

Thanks much!