I had to do this. My xAH was calling all his family and me, sobbing and telling everyone they could have what they wanted of his and that he loved them. He told me he had thrown his stuff out the window and he told his mother that his roommate had kicked him out. He told everyone "Thank you for everything you've done. Goodbye."
I called the local Police Station (he was living in a different city, Thank G!). They went and picked him up and brought him to the Emergency Psych ward. See... here's the thing, at least in NYS, they ask you very specific questions... "Do you want to hurt anyone?" "Do you want to hurt yourself?" if you answer yes to these questions, they are obligated to hold you 72hrs.
When I called the Psych ward the next day, he was all "Oh, I was just sleeping. Why did you think I was gonna kill myself?" BS! They can't hold you unless they think you're a threat to another or yourself. His Aunt ended up getting him out (Shame, shoulda stayed there) and the doctors said: "Typical alcoholic behavior."
No Kidding! Ask me how many times he ended up in the emergency psych ward - once for pulling a knife on me, another for calling the cops saying he'd raped me and gone insane after too much whiskey and coke - and no, that's not the drink I'm talking about.
Ai, the things we find out about the law and mental health institutes!