A psychiatrist friend of mine once commented about suicidal people who tell others of their state vs one that doesn't.

His summary is that the ones who tell others haven't yet really decided. They're still reaching out for help, for some other way. The ones who have really made the decision, who have given up all hope for an alternative course of action, are the ones who don't say anything.

Because why would they? From their perspective, they have nothing to gain by doing so, and would cause a lot of additional trouble to themselves and their loved ones if they did.