Wow, What a #%$&%^ of a woman. I don't understand people like that.

They are in their own selfish world.
I guess I would have said. "Gee, I think he took it with him and you'll have to go get it out of the coffin yourself." Hopefully an absurd statement like this would make her stop and think of what she just said. And maybe make her a bit shame-faced?
Sorry you had to experience something so heartless.
And there is NO etiquette to something like this.