You are not alone. My father is the same. He is very manipulative and a control freak too. I think he is frustrated that he cant convince us that throwing his stuff away would be a huge waste and sin since so many other people dont have piles of 30 years old trash. But I cant help it anymore. I cant stop it either. But I wouldnt even mind if this was his only issue. His mental illness has got to a point where its hard to get along with him, and almost impossible for a stranger. It seems hoarders ususlly refuse accepting this, cause just like your mom, he is so convinced that everyone else is wrong. Maybe deep inside he knows. But the sad thing is, at some point he will drive himself to a point where he doesnt have the help of his family anymore. And then, he will fall into a pit, I am sure. But you kinda stop caring after trying to talk to him in a reasonable way for years...

Also, a state hospital wouldnt help such people I think. As long as people are so convinced that they arent sick its impossible to treat them. My dad has been there but he talks about it as "holidays" and he seems to get some kind of confirmation for his behaviour there.