Yes, if you feel he is in danger, you should urge him to see a mental health professional. If he is schizophrenic, as you say, this may prove to be a difficult task. Are you sure about schizophrenia? Is it perhaps dissociative identity disorder? Perhaps you should read on the suspected disorder(s), and try your best to narrow down the possibilities, so you have a better understanding on things. You can then see how you should approach the situation. Regardless, he should see a professional.