Need advice for a dog that is being treated badly

hi, I have a neighbour who bought a dog, a boxer breed, female. Before turning one, they breed it and left it outside tied with prolly a 1.5meter metal chain. Under the sun, under the rain. It is never let out, go for walks or anything. The nails are growing long, it shits and pee where she sleeps. My family have voiced out and offered to help take for walks if they are busy. I work from home, so I have been observing them for a while but it just breaks my heart that the dog is so young and it is never been loved or even walked. Any advice what I should do or who I can contact to help? And also, day by day. It is getting skinnier and weaker.