I want to piggyback on what @hearkat and @mass_pike4 said. One reason (and it may be the reason, except when physical illness is involved) that people think about suicide is because they are in the deepest pain imaginable. In that state, at least in my experience, one believes that one is unloved and unlovable and undeserving of love, anyway. I.e., anyone who did claim to love the suicidal person is either deluded, mistaken (in that they don’t have full information), or lying.
As such, suicide is a call for help. It may not be a deliberate call, but it is the only solution that a person can think of that will release them from the pain of being a horrible, despicable, inhuman alien.
When I was thinking of suicide, I didn’t really want to blame anyone or use it as a call for help. I felt like that was manipulative, and would sort of defeat the point about love. If someone loved me, it had to be because they wanted to love me, not because I was manipulating them into it. Thus, I gave noone any help in loving me. In fact, I tried to do everything I could to be the most unworthy person I could be. If someone could voluntarily see enough value within me to actually love me, and demonstrate it by going out of their way to be with me when I was pushing them away nearly as hard as I could, then I might believe it.
It’s such a trap that I put myself in. I knew it was a trap. I knew I was bent on destroying myself—it was the only thing that felt right, even if, intellectually, I knew it wasn’t right. So, seeing the trap, I still walked into it. Unfortunately, if I ever feel like that again, I’m sure I’ll walk knowingly into the trap again.
So what others have said—reassuring people they are loved, although you don’t like what they are doing—probably will help. I think people want to push the people who love them away, by drinking and being miserable and hurting their loved ones, partly because they want to punish themselves, and partly because they want to test you.
The trick is to find a way to get a complex message through to them. The message is that they are a valuable and lovable person (and it helps if you don’t merely say that, but repeat the reasons why you believe that over and over), but you are not going to let them ruin your life along with theirs. In other words, you will love them, but they do have to find a way to let you help them—a way that does not allow them to manipulate you.
Like others have said, urging the person to get treated, to check themselves into a hospital; to go into detox; whatever it is, is a good way to deal with this. You have to do this over and over. It’s your “broken record” message. It has to be consistent. It shows that you care enough to try to get them to help themselves.
However, the part about not letting them manipulate you, is also crucial. That also sends a message. That says you care about yourself enough to take care of yourself. It is a model that perhaps, seeing it, the sick person will try to emulate. I don’t think of it as “tough” love. It’s responsible love. It’s taking care of yourself love. You would love to take care of them, but you can’t take care of yourself at the same time. Your priority is yourself, just as their priority should be themselves.
The thing about alcoholics is that they usually have to go through detox programs over and over again. Some can break the habit on their own, but that’s fairly rare, I believe. Your message, I believe, has to stay consistent. Get professional help. I love you, and for that reason, I will help you solve your problem by getting professional help, but I will not help you do anything else.
I do believe that there are underlying reasons for people to “self-medicate.” Depression is a common reason. But pain of any kind can be medicated with alcohol. I know some people say that you should deal with the alcoholism first, and then the underlying problem. I lean more towards the other way around. Deal with the underlying problem, and you can deal with the alcoholism. Since I’m not really conversant with alcoholism and alcoholics, I could be way off.
I suspect that detox programs are usually too short to teach people the skills they need to deal with underlying problems. Support afterwards then becomes very important. The alcoholic needs new patterns—staying away from people that share the problem; getting onto a more regular schedule; doing more productive and useful work. They need to do things that will help them feel better about themselves. And they need to continue working on the underlying problem(s).
I doubt that many people get much help this way. I’m pretty sure that AA provides this kind of support, but I don’t know if it’s enough. Still, people have to make a choice—to continue working towards a way out of the pain. Love, as they say, is the answer. But it has to be delivered in a productive way, not a way that helps the alcoholic continue to drink.