What do i do to save the neighbors dog?

i visit my grandparents a month every year and next door there's this family with a dog separated by a fence. the dog is the nicest, most beautiful, most playful and energetic dog i've ever seen, but every time i walk by the dog is in the fenced off area, and she's been there for as long as i can remember. (i remember being ecstatic once when i discovered there was a puppy next door, and that must have been like six years ago.) i'm sure the owners put out food and water for her every day, she looks healthy, but she's always caged up and it's absolutely awful. i have NEVER seen them bring her inside or take her out of the fenced off area. she deserves so much more than running in circles in what's practically a cage for years and years, but the family isn't technically abusing her so it's not like i can complain to an animal abuse place. and i know it's a little silly that i ask but for some reason it just now really hit me how badly she's being treated. does anybody have any ideas of anything i could do??