hi Chou,
my mother is not an alcoholic, but had a very difficult time in the wake of her divorce from my father, we went through a period where she would put the phone down on me a lot, and I would ring her back to check she was ok etc, one day I said "if you put the phone down on me again I am going to assume you no longer want to talk and I will not be available to speak to", she tried it once more and I held that line, she didn't do it again.
before I drew this line, she had talked about killing herself and then put the phone down. I called 999 (UK
) and called for an ambulance for her, I kept ringing and managed to get hold of her and she was very very angry that I had called them, and embarrassed when they turned up, but she never did it again.
ringing the appropriate services here is win-win, and there are very few of those situations, if he is seriously suicidal, the people who know how to help him are there and can assess him, if he isn't and is trying to manipulate you (intentionally or otherwise), he gets the consequences of that, and best of all, you, his child, do not have the anxiety and burden of trying to work out his intentions.
if he does that again, I would not respond to him at all and call 911 straight away and be at peace that the professionals are on the scene.