I think my brother is/has gone nuts

[jambo101]

5-6 years ago my then 45 year old brother was a fun loving guy,we spent hours on our motorbikes or cruising around in our sportcars,we were up for any kind of airshows, bike shows ,boat shows,car shows etc.
Fast forward 6 years, he has now sold all his toys in favor of an outlandish collection of guns,his wife has left him along with most of his friends, he's taken up residence with a tough old b..tch and they live in a trailer in the woods with 4-5 pitbulls roaming around the house,to protect the guns i guess, he's given up his propane delivery job in favor of an armed guard job ,where he gets to wear a uniform and walk around with guns.
Its now hard to even talk to the guy as every topic turns into an obsessed diatribe about/against the government coming to get us,boogymen are around every corner,drones are watching our every move,in his world conspiracy theories are all true.
He spends most evenings obsessed with his many rightwing websites, talk shows and forums.

I'm now seriously worried he may shoot me or a family member if one of our conversations dont go his way. The guy has basically become psychotic.
I dont know what to do as he now sounds like he's gone absolutely batshit crazy.