Hello fiona,   If it turns out he has schizophrenia and his family is in denial about this, that is not good news.  The longer they wait to get him treated with medication and therapy, the worse the illness will progress.  If his mental state diminishes sharply because of his parents neglect, he could be taken away from them by Child Protective Services or whatever agency in your town or city is responsible for this.   My answer to you is this: if you are his teacher in a classroom and observe what you believe could be symptoms, it is your right if not duty to alert the professionals who are in the best position to determine what's going on in his head and make an accurate diagnosis.   So do what you feel is the right thing because I'm not sure what you mean when you use the word "teaching," as in, you need help teaching him.  You do not need help teaching him from how it appears.  You need help in getting him help.  As you have said there are mental difficulties and a history of violence in his family.   So if you believe you must take action, you have your answer.   If you are asking for methods of teaching a young person with schizophrenia, I would suggest something else: be patient, bring up one concept at a time, and give him ample enough time to answer.   Right now however that doesn't seem to be the main issue.   Regards, Christina