How to Get Someone Put in the Booby Hatch?

I've got a co-worker who I'm 100% certain is suffering from mental illness, probably some form of depression. The guy is utterly lifeless, belches and farts all day, and smells like a stall. No difference from most office workers there, but he also mutters threatening statements under his breath, admits he spends weekends alone in bed with the curtains drawn, and occasionally talks in a cartoon Mickey Mouse voice for no reason at all. (He's 37). Recently disciplined for downloading porn at work, eats Doritos for breakfast and weighs about 21 stone. I'd like to get rid of this guy anyway, but I think it would be more humanitarian if I just told somebody I think his elevator is stuck somewhere on the mezzanine level. Or should I just call the men with the butterfly nets? I'm serious, once this guy came back from the loo with a copy of the Sport, theatrically denied reading it (nobody even asked him) and then preached about masturbation being against his parents' religion, then talked about a girl he saw on the Tube that he'd "Like to get to know, I'll make sure I'm at the same stop next time tomorrow..."