If he's suffering and it looks like he is - I'd call. I had to do that on a neighbor and if I posted the pictures I got of the dog you'd get sick...they're too graphic for this site....I hung off my fence and used my zoom lens to get photos of him and emailed them to the Houston Animal Cops. They were here in less than 24 hours.
My neighbors excuse for the neglect was MONEY - yet they had just bought their kids a huge JungleJim - bigger than my whole backyard.
It's not alawys the money ....it's about being LAZY AND UNCARING and it's just plain wrong to keep a dog and not give it medical attention. She doesn't deserve him & it sounds like he needs your voice .... He may end up in a much nicer home.....
but if you do call - make sure they don't put him down if someone comes to get him.
GOOD luck - It's so sad there are thousands more like him out there when it doesn't have to be like this