By that, I mean amateur radio operator. Since the amateur radio service rules include RF exposure safety rules, and we all have to know how to do the math, they will likely be able to reassure you that the situation is safe. The rules for amateur stations are similar to the rules that all other RF transmitting services generally have to follow. Since the condo is not part of the fenced in enclosure where the antenna is, it's part of the 'uncontrolled' space (that is, space where the general public - particularly people not owning or working on the antenna). The exposure limits for uncontrolled space exposure are much stricter than controlled space (that is, any place where a person could be without having the transmitter shut down).
In all likelihood, the antennas in question are aimed such that the energy won't be going into the apartment. How can that be? They have to pay to generate the RF, and they want as much of it as possible to hit the opposite antenna rather than be used to irradiate a nearby condo.
They're selling this unit for a song likely because of the "what if?" thoughts you yourself are having. Educate yourself and turn this into an opportunity to acquire an undervalued property!