This relationship became a bad thing. It should be over now. He may deteriorate and decompensate further. That will eventually cause him to come to the attention of the authorities. That may result in him getting some medical attention. Don't think you can rescue him. You can't.

Did he manage to cross international borders prior to becoming your boyfriend? If so, he is not helpless, or he has had some other network of support.

It sounds like having a girlfriend actually destabilized him. So you need to back away from him, as he has wanted you to do.

On a deeper level, you need to look at your tendency to get entangled with very disturbed individuals. That may not be the best approach for you to use to build a healthy, successful life for yourself.