I don't buy it. I could sell any house in an hour if you let me set the price. Their actions are not fair to their neighbors, it's not the neighbors' fault they raised a junkie.
I'm sure they could probably sell their house if they were willing to take a big loss on it. What sort of person would want that to happen to them. Don't they have enough trouble now? These people don't sound like they are wealthy and now they have to raise a child during what should have been their retirement years. And to say, "they raised a junkie", makes it sound as if you blame them for their daughter's drug problems. Do you have any idea how many good parents have had their grown children go "bad"?