You have asked many good questions. The situation is complicated. His safety and yours are paramount. I am not certain if you still are in contact with him but if you are and if you believe that he is a danger to himself or others, then do not hesitate to call the authorities or a local mental health crisis team. They can go to his home and interview him. If they believe that he is mentally unstable, to the point where he may be a danger to himself or others, they would take him to the hospital for an evaluation. He may be angry at you for calling the authorities but as I mentioned your safety and his is the priority.
I cannot determine if he has schizophrenia. That is too difficult to determine over the Internet. He does seem to be having delusions. He is also experiencing paranoia. Generally, if delusions and paranoia are left untreated they will become increasingly worse. It is also concerning that he is unwilling to seek treatment.
You should contact his family, or at least the family member he is currently living with. Tell them about your concerns.
You can’t force anyone into treatment unless they are a danger to themselves or others. Generally, in most states, that is the law. He may have delusions and paranoia but even with those symptoms it can be difficult to force someone into treatment unless they meet specific criteria designated by the law.
There is no “easy” way to deal with this problem. At this time, it is important to be vigilant. As I mentioned above, contact the authorities or a local mental health crisis team if you believe that he is a danger to you, himself or others. If there is a local crisis team in your community, it would be advisable to have their phone number available. You can usually find that information by looking in the white pages or by doing an Internet search with keywords such as “behavioral health crisis intervention” in your state or community. I do not know your specific location but here is a link to information about a Maryland behavioral crisis team. You could call them and ask for their advice about your situation. Please let me know if you have any further questions. I would be happy to answer them. Thank you for your question.