[lily.]

If someone is really going to commit suicide there's little or nothing you can do to stop them.

In my experience, when someone actually goes through with it, often their loved ones had no idea they were even thinking of it.

Something that's hard to deal with is the "attention seeking" behaviour some people display where they tell their loved ones they are going to commit suicide when they actually have no intention of doing so. That is heartbreaking for everyone around.