“He says that the world will end on April 14, 2065, at 5:17am”
That is not at all what he says. He says that is the date when his data TOLD him the world would one day end. As in, he was doing his calculations and realized the world was going to come to an end. Not that the bombs dropped on that exact day.
“He's there on other business, but he is invited to speak with Mr. House.”
What business is that? He’s literally there for House. Did you watch the show?