My friend is a paranoid schizophrenic, his physical health is failing what to do?

Get him to doctor: Your friend's situation is complicated and the best thing you can do is to get him to seek care from a physician.

Know your limits: It is often impossible to help people like this. Often you cannot reason with them. If he appears to be a danger to himself or to other people, be ready to call the police or the mental health caregivers. I am glad you consider this person your friend despite his illness -- usually these people are terribly isolated. It's a credit to you. Ultimately, you can't assume responsibility for his life.