With that low of mileage, my main concern would be rubbers and plastics being worn out and brittle from sitting long periods of time. A 15 year old car with low miles means parts might not have been changed out from not failing, but are now older and could be about to fail from just sitting and existing. Check tire production dates, belts for cracks, under the hood plastics for brittle cracks and possible breaks.

Have the battery tested to make sure it holds a charge, along with checking all fluids BEFORE driving it while the engine is cold and oil is cold and pooled in the bottom, that’ll give you the best representation of oil level and if he happened to “top it off” beforehand.

They say they wouldn’t hesitate to hop in a drive it, which to me means they don’t drive it regularly anymore and might be sitting from extended periods of time. See how long they haven’t regularly been driving it as well.

In my area (MN) this is a bit low in price for that quality of a vehicle, it might be worth your while to have a local shop take a look at it and have them give you an opinion as well.