I notice ur in the uk. I presume this guy has a CPN? Can you contact his CPN? Even if you don't know the name of his CPN you can ring the office where he lives and speak to the duty worker. Give his name and explain what's been going on and that he's harmed himself in the past. They will take it from there! They will arrange to see him and make an assessment. That way it stops you from becoming overly envolved and endangerinng you and your beliefs. Phone them in the morning as there should be a duty officer available to talk to!!!

Good luck hun and let us know how you get on- I know it's difficult know but your friend will appreciate it when he comes out of his psychosis!! Hugs xx