There are different kinds of mental illness that can cause hallucinations, not just schizophrenia. More to the point, these illnesses are treatable. But in her case, I'd think it possible that she's having a stress response and that with therapy might actually resolve and not trouble her again. In any case, finding the right support for your daughter right now - starting with her pediatrician - won't be nearly as hard as what you've both already been through. Also, you and your wife need therapy after that too!