I know how terrifying it can be to have someone tell you they are going to commit suicide. My ex AH did it and now my AS.
My AS is in a relationship where i had to call the police to stop her harrassment. They fight, he cuts himself and threatens suicide.
I called the police and when they talked to him he said he was not suicidal, or homeless. Then he starts posting on FB about suicidal thoughts. I called clinics and found numbers to give to him. He said he was going - never did.
I finally drew the line in the sand and my AS became nasty and went NC. I have talked with a counselor and I realize while my son may actually commit suicide, on purpose or not, all of my worrying will not help.
I actually talked with an EMT and he said the myth that is they tell you they are suicidal they will not do it is not true. The one fact is that if they want to there is nothing you can do to stop them.
I agree it is the ultimate horrible way of manipulation and my advice is the same - call 911 and report it.
(((huggs)))