What happened to the crazy people from Atherleigh hospital?

Answer 1

Most of the 'Crazy People' were Alzheimer's cases. They're dead now

Whereas it is certainly true that most of the people at Atherleigh probably are dead, it is not true that "most" had Alzheimer's disease. There were two pavilions of forty people each. They were what then were known as "part three" residents, old people in need of some care, but not "mad" whatever that might mean. There was also a sixteen bed ward of chronically ill children.