New here and have a pretty scary situation.

Girlfriends brother has extreme delusions and paranoia. He believes people have been following him for 10 years. They can hear him through his phone, TV, radio, etc.

To make matters worse, he is a drug user (cocaine, marijuana, crystal meth). While using, he is aggressively defensive. If you don't believe him you are part of the conspiracy. He maintains his story whether high or sober.

So, what do we do to help him?