Here's some links for your neighbor.
The Facts About Chaining or Tethering Dogs | The Humane Society of the United States
You may want to get him to re-consider & tell him how cruel it is to keep a dog tied to a tree. I just can't understand what people are thinking when they get a dog only to leave them outside on a freakin chain or rope.
It should be against the law everywhere and is in some states
cbs11tv.com - New Law Prohibits Leaving Dogs Chained In Backyard
I have a picture I will not post here (too graphic) - but many dogs die a slow agonizing death due to being tied up.