...as I am standing there in complete disbelief, this lady seriously has the guts to pull this crap at my great-grandmothers FUNERAL?..
First, my condolences. Seems like you will be missing your grandma. Maybe you have some of her in you. Second, I'm so sorry that your mourning got so disgustingly interrupted by all that nonsense. Feel proud, though, that you handled yourself with grace.
Many JWs truly believe that preaching to people in mourning is supposed to make them think that they can see the person they are mourning again in their stupid "paradise on Earth". I consider what they do at funerals to be the most disgusting, truly irresponsible, tasteless, classless action.
I'm so sorry you went through that. Again, my condolences.