Blocking driveway of person(s) with health conditions

This car has been parked outside my father in laws house previously and has now returned for the last week. The white Mercedes Benz above is untaxed and is blocking half of their driveway. My father in law suffers with strokes and is extremely crutial that my mother in law has access to her vehicle at all times incase of an emergency. The vehicle is large and creates a very small space which is outrageous considering the amount of time they have to get my father in law seen from his episodes. Please can you get this vehicle moved/removed asap to ensure we can tend to his needs in the case of an emergency.