I would hardly call Souji "normal." [ Dryly; he wouldn't even call himself normal. ] But your explanation stands within reason.

[ He would ask about the tuberculosis but...does Kashuu know. Where in this timeline of theirs is Souji at, even. He doesn't want to assume, only to have Souji think he is keeping secrets from him for his own good. ] So I take it these ghosts possessed someone, and then made things difficult.