Well, his family is what WBC is mostly composed of. So I suppose you're right about this. Nobody wanted to talk to them before, and that's not gonna change.
Even though I'm an hardcore atheist myself, I still think celebrating somebody else's death is dumb and absolutely not necessary. I can't think of any scenario where this would be acceptable.
Seriously, guys, this is a forum thread, not a random Facebook post. 
Normally, I don't "celebrate" deaths of other humans. However, there's a certain category that live only to make the world a worse place. Militant extremists of all sorts, psychopathic murderers and people who can be, by any reasonable standard, objectively called evil. Really, I can think of nothing good that came from that guy, and I'm glad he's finally gone. It's not that he died, it's just that he's not here to hurt dead soldiers' families, nor anyone else (the list is long) anymore. And this is a very good thing.