Miserable

We have a situation at home that is driving me to distraction.
Our across-the-street neighbor recently moved in to his mother's old house, and he brought with him a dog that howls constantly - all day long - when he and his wife are at work.
They have five acres, but it is only fenced on three sides, so they have been tying the dog during the day. This is his daughter's dog, and he's pretty much stuck with it.
He is aware of the problem, and is trying to cooperate. Meds the vet recommended only worked for a day or two and now the poor dog is wailing again.
Any suggestions at this point would be appreciated.