Looking at a very low mileage R53 driven about 1K miles per year. Current owner has owned the car for 2.5 years and has done nothing to it.

Is it ok for oil and coolant to sit for that long without being used?

 

I would flush the CRAP out of the cooling system.....
Oil....likely ok,,,,but a couple oil changes in quick succession should be fine IMO...sure a bit of surface corrosion MIGHT have occurred during the sitting...that would be scuffed off when stated....that's why I suggest a couple oil changes..
then do a brake fluid flush.....
You do not list an region/location.....
IMO if it was in a cooler area...better...corrosion slows down in the cold....
that is why AN unheated dry GARAGE IS BETTER THAN A HEATED one for storage IMO.

 

PS
I would check the cabin filter....when a car sits...mice/rodents can move in....
and look for chewed wired under the hood...same issue.

 

Car is located in s. cali.

Thanks for your input.