Yes, it can definitely be schizophrenia. No doubt about it.

She needs to get help.

I'm no doctor, but I have schizoaffective disorder/bipolar disorder. So I can relate to some of it. I don't hear things, like voices and such. But she obviously does.

Somehow you have to get the ball rolling on getting her some help. That might prove to be very difficult with her thinking everything is fine. But you really should try. At least make 1 appointment with a doctor. Hopefully she'll cooperate. I remember my first parent/psyche doctor family meeting. What a challenge that was.

Really sorry to hear that you're both going through this.