Kyouya could've explained away the first part of the story. Many ancient civilizations on Earth believed that certain members were the children of gods, and so while Homura believed in his parentage, it didn't mean it was true. But this other stuff... you couldn't be confused about living for several centuries or dying unless you were actually delusional.

This was a mental hospital, after all. While Kyouya was certain that none of his friends deserved to be here, there had to be at least a few legitimately crazy people in this place.

But Homura behaved so lucidly. And despite everything, Kyouya was interested in the peculiarities of this man. Whether he told the truth or not, Homura was definitely a character.

"So," Kyouya began at length, after enough time to keep the incredulity out of his voice, "you're telling me that you're a dead five-hundred-year-old demi-god. Approximately."

He still sounded a little skeptical.