Life is hard sometimes, isn't it.
It's not your fault.
You can't control others destiny. We just have to accept it.
Anger is natural.
But what's done is done.
You can't save everybody. Every action has consequences. Maybe you think you could have helped, or averted this, most likely, not.
People are free agents. With Free will.
Dealing with death is very difficult. But everybody is responsible for their own actions. We all die eventually. We can't control how it happens. And you cant' control people's spiral downwards. You're only responsible for your self. "Everybody Goes Away in the End" Yeah, that's true.
Just do everything you can to keep level headed. (Within reason, within bounds, sure...have a drink, whatever gets you through. I think you said you had a problem with that? anyway...) Naturally, it's a trying time, psychologically, emotionally, to have such news , hit you. It's worse when it''s unexpected. No time to mentally prepare. It hits you all at once. There's no way to feel good about it, or process it, beforehand.