I'll try and keep this as succinct as possible.
My brother, 37, has struggled with his mental health for at least 20 years. We grew up with an abusive father, and my brother bore the brunt of his abuse. He was emotionally abusive, telling my brother he wasn't a man a just generally doing everything he could do emasculate him, but also physically abusive. One time our father pushed my brother (then at university) from the top of the stairs- brother broke his collar bone- my father was not reported and faces no consequences.
My brother has never held down a job, never lived independently, struggles to maintain friendships. He's had one relationship that I know of, with a woman a decade older than him when he was in his late 20s. He's sought help over the years (re his MH) but never really committed to anything.
Fast forward to now- my father finally left my mum a few years ago, and my brother has just spiralled since. He's becoming increasingly psychotic (or paranoid I'm not sure??). Initially all his delusions concerned my father, so oftentimes we'd suspect there may be truth in what he was suggesting, but now he's turning on my mum and younger brother and others. He remains convinced (since March) that my younger brother had an affair with his ex gf (which is ridiculous). He even called the police accusing my younger brother of something (we don't know what!). The police of course recognised my elder brother wasn't well and left things.
Soon after thus incident we arranged for him to stay with extended family abroad. They kicked him out after a week. Following that, he's managed go get kicked out of 2 separate hotels. He starts fights with employees, makes inappropriate comments to female employees and customers, and defecates on the floor in his hotel room.
Now, in the months leading to his departure I contacted his private physiologist who disagrees that he's psychotic and suggested he's got PTSD from my father's abuse. Meanwhile, my younger brother started sleeping with his bedroom door locked, and my mum started hiding the knives in the house. I then contacted his GP who agreed to see him. He refuses any further support or referral and the GP is not able to discuss his case with me. When the psychosis was particularly bad, on more than one occasion I contacted First Response. As first they seemed open and helpful, but this changed as soon as they spoke to him (I really dont know what it is he's telling them). Subsequent attempts for further assessment or even assistance has resulted in them reminding me that he's an adult "with a right to privacy".
He's due to return to the UK this weekend. He is incredibly volatile at present. He remains delusional. He's emaciated having stopped eating properly months ago. He rarely sleeps at night. Doesn't remove his sunglasses even when indoors. He is weak physically but can be aggressive and provoking. He'll start fights with random people when outside. He does weird things that attract attention when out. My mum will be back caring for him alone (while my younger brother tries to avoid him to avoid conflict). My mum herself is in ill health and financial ruin following decades of my father's abuse.
What do I do? Who on earth can I contact given I seem to have exhausted all normal avenues (GP, first response etc)?
Please help