Look at this object.

https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-location-climate-weather-file-access.html#sitelocation

According to the docs, "Only one location is allowed."

Be careful though, because "Weather data file location, if it exists, will override any location data in the IDF."

You can access the lat/long of the facility by examining these fields:

https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-location-climate-weather-file-access.html#field-latitude

https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-location-climate-weather-file-access.html#field-longitude

elevation might also be useful.

https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-location-climate-weather-file-access.html#field-elevation

Using latitude, longitude, and elevation, you can probably calculate the distance between buildings. What is the application for this? Based on what I can infer, an IDF represents one building, so you would have to query multiple values from different IDFs to calculate the distance between buildings.