Because it was too late and he was into 2 weeks of Pneumonia
I'm pretty sure that's not how it works.
Pneumonia starts to go away after 2 - 3 days of treatment, Boomerangdog would most likely be getting better right now.
It's not irreversible, even after two weeks of it.
Also the fact that you don't know what a troll is and yet you say you've been on Minecraft forums before. They would have most likely told you, and if you have bothered to find out how to change avatar on them I'm going to assume you've been on them for a while which just adds to the fact that you would know what a troll was.
Thirdly, it's weird how you post on a forum exactly when he dies. You'd think you'd be telling, uh, I dunno: all of his relatives and real friends before telling us. That and grieving. To me if Boom really has died, I think it's pretty disrespectful in my opinion that you are telling some people on the internet about his death before everyone else. Disrespectful to the other people of course, not him.
Assuming he DID die two days ago, why was he in hospital? If I remember correctly (and I could be wrong on this) Pneumonia doesn't cause lots of pain randomly when you're about to die it just gives you a painful but quick death.
Surely when he died you would just send him to an undertaker, not the hospital first. He wasn't in hospital before he died either, because he was posting on the forums and such two or three days ago that and the fact when you have Pneumonia they just give you anti-biotics to take. He wouldn't of used the hospital computer because I'm pretty sure they don't have Paint.NET to make the crumbling stage's logo. He even said on the 7th of April he was at home, so yeah.
All in all if Boomer HAS died I feel very sorry for you and send my condolences, but really there are a lot of plot holes in the story and if you answer these maybe people will believe you more. : I