1980 Oldsmobile Alero GL

2001 oldsmobile allero. Car was friends mother's who passed approx 8 years ago. The vehicle was sedemental too him so he had on side of house. But West valley ordinance is fineing him for no valid registeration. Car runs great , old fuel was removed tune up was done. Needs new tires and has engine light on but the code reads sparkplug and the owner is a older guy and he says that the back plug might not be tightly screwed I he has trouble reaching it... Anyways I'm the middle man