Cats rescued from a horrible situation

[Catherine]

I have to say that the house is worse than any place I have ever seen and I mean a lot worse. Thirty cats and a ferret were found in a faeces "smothered" home. It was the mother's house and her son left two cats in there and let them multiply. They were not cleaned or provided for. He has been charged and so he should be. Some of the cats had to be euthanized. 

http://metro.co.uk/2017/08/10/over-30-pe...w-6842489/

I am amazed that someone would let a home get into such bad shape. The cats couldn't help it. They were desperate and trapped in the situation. The cats are out of it now and some will even find homes. The house will probably have to be demolished. I don't think gutting it will be enough. What was the son thinking when he let things get into such a bad state.
Why did none of the neighbours complain? Someone must have been aware of what was happening.

I am actually shocked by the condition of the home.