I'm afraid he is quite sane. That is another person. You see Jenova the Space Bitch he mentioned is an alien virus that infects the soul as well as the body. Essentially transforming the infected into the virus. The infected also have a sort of hivemind state with a leader they call Mother. However someone who is of exceptional strength fan topple the Mother and become the leader themselves.
"All worlds begin in darkness and all so end. The heart is no different."-AnsemWhat's with all the problems around here? I swear every single time I've been here there's always been at least one problem that I haven't been bothered to deal with. -starts fiddling with some playing cards taken out of his pocket, some of them bursting into flames and dissipating as he chucks them up into the air before taking out more cards when he runs out-
"You'd never do something as irrational as dying."

Though I hope you did not mean anything by "a little something."
"All worlds begin in darkness and all so end. The heart is no different."-Ansem