In the book it says that Olivers Grandfather built the asylum. John Saul, the author, wanted Olivers Great Grandfather to build it, not his Grandfather.
Wrong! Oliver's grandfather, Charles Connally, built the Mansion for his wife and it was later turned into the asylum. In the first chapter (page 6 in my book), Oliver is talking to his uncle Harvey about the forthcoming demolition of the asylum. He says, "Your father built it, Uncle Harvey. Aren't you just a little sorry to see it go?" Harvey is Oliver's mother's brother.
Before you make any comments at all you should read all 6(six) books first, because in the 6th one, John Saul added some personal comments where he admits he made the mistake.