I wouldn't be ecstatic, nor would I be upset. I'd say something like, "Oh, we'll that's sad." And that's that. I mean I wouldn't act like nothing happened because that'd be cruel but death happens all the time to anyone. It can happen to anyone, anywhere and anytime - it's how life is.
It would matter to me how he died. If he was murdered, I would probably wouldn't be happy at his his death but I'd want him to get justice. If he were to die by nature causes.. well, I'd be neutral I guess.