I have a friend who's been chronically depressed for the past 20 years.

He always confide in me about his feelings and dark ideas, claiming that therapy (that he used once, for one visit) didn't work and therapy is useless.

His girlfriend broke up with him after he confessed having feelings for someone else, and he now wants to kill himself.

He reached out to me tell me about his intentions to end his life. How he was gonna do and when.

His ex also reached out to me to tell me he's been acting very manic.

Constantly trying to talk to her and patch things up. Saying he's better one moment, and 2 hours later saying he wants to give up.

As a caring friend, I don't know how to handle it.