Many have said that Waugh was an unpleasant man personally. I think he once said that if not for God's grace he would have been a lot worse. But his novels are, in fact, brilliantly moral. I read the whole article you linked, and I can only say that the author doesn't understand or sympathize with Catholicism, or he's have a completely different take on "Brideshead Revisited."
The novel, like all of Waugh's novels, is full of sinners, but in point of fact if you read it with understanding, it turns upon a miracle of grace when the old man dies, and the conversion of the central character years after the main action took place. That is when Brideshead is "revisited." Most critics simply don't get it. It's one of those novels that demands to be read several times.
Fake but accurate?