This is going to sound very harsh but I can't help it..............Why the hell did nobody take the dog to a vet!?
Are you kidding me!? The dog can't move and is just laying there throwing up and you leave him to suffer and die.
Perfect.
Then we'll check out what might have killed ol' Gus.
MY GOD
Do you think anyone would think to take you to the doctor if you were laying there not moving and throwing up?
It's called responsible pet ownership. Look that up on the internet.