My parents aren't taking care of my dog!!?

I'm in college, home for the summer. I'll be gone another year and I have a cavelier king charles spaniel. My parents are new to actually taking care of dogs since they're used to leaving the dog to practically survive on its own outside. They leave my dog outside all day and sometimes at night(in the winter and the summer heat!) because they say she's too dirty(because they refuse to give her a bath or take her to the groomers!). My parents leave the gate open all the time to let her wander around the neigborhood! Then they'll only buy the cheapest dog chow you get at the grocery store. And my dad won't let me have a doggy door installed. It was probably a mistake getting a dog in highschool but it worked when I was at home. I don't want to get rid of her because she's my first dog and it would be like getting rid of my baby,yet I'm constantly worried! What should I do!?