Hello and thank you for taking the time to read this. I am in southern California USA and I think my brother in law might be severely mentally ill but I am not sure how to get him help. This is going to be long because I want to fully explain what hes been experiencing. A tl;dr is at the bottom. Here's what happened:

Last night my wife gets a call from her brother. He's frantic. He was mumbling nonsensical things for a few minutes before my wife could understand what was going on. He had fallen off his bike, hurt himself pretty bad and was in the hospital. He's 40 years old and since I have known him, he's been just a little off but this was a whole other level.

He started rambling about how he was in a fake hospital and that the staff were planning on taking him away through the underground tunnels that run under the city. There are of course no such tunnels and we aren't sure where he got this idea. While on the phone he heard a beep come from a piece of the equipment in the emergency room. Why the fuck is there a beeping?! There's nothing connected to me! Why would there be beeping?!

We try to get through the rambling and ask him what hospital he's in. Finally he asks a staff member, and she wasn't really sure. Turns out this was her first week in this hospital and she wasn't completely familiar with the area. This set him off even further. See! This bitch doesn't even know where we are! How can she be a real doctor?! They are going to take me away!

At this point he has to get taken for x-rays so my wife and I get ready to go to the hospital. On the way there he calls back and begins raving about the underground tunnels that he KNOWS people have disappeared in. Finally we get there and he is pacing around the small ER room they put him in, rambling about random things. My wife tries to calm him down but he keeps talking about the underground tunnels. He now informs us that there are abandoned hospitals in a nearby city that they lure people to and capture them. This of course could be one of them

He was pretty argumentative toward the hospital staff because he felt they were there to hurt him in some way. He kept insisting that we call our family members to tell them where we are so that if we were to be captured, someone would know where we are.

This continued for a little while longer but once we were discharged, his thoughts and speech continued to be disorganized. He told us that his astrological sign was ares, so he would heal very quickly and that he wasn't worried about the torn ligament in his shoulder. Then he jumped to taking about god and how he knows that god is made up of radiation or some sort of energy all around us. He then said that he sent a telepathic message to his sister (my wife) and told her to come to the hospital. In the past he has mentioned to my wife that he believes he is superhuman in some way.

Once we got him back to where he was staying, he insisted that he give my his phone number. He told me that some sort of world wide catastrophe is going to happen and that I needed to contact him when it did so that he can come find us.

My brother in law had always been a little bit off I think but I have never seen anything like this. He seems to have lost touch with reality. He doesn't seem to want to listen to the evidence against his paranoid delusions. It's pretty scary. I don't think hes a danger to himself or others at this moment but I know he is capable of lashing out if he feels threatened. I need to get him some help.

What kind of professional should I seek out to diagnose him?

How can we convince him to see a professional?

Does anyone have any experience with a family member like this?

tl;dr: Brother in law seems to be having paranoid delusions, out of touch with reality. Desperately want to help him lead a normal life. Please see above questions.

Thank you so much for taking the time to read this. I sincerely appreciate it. Feel free to message or comment any advice. Thank you.