If she were just about anyone else, I would be thinking that it must be upsetting for a responsible person to lose a pet.
But we are not talking about a person who is responsible, so instead I only feel sorry for the pet.
My guess is the dog's fine and she's just keeping it in hiding. This is all to get back some of the thunder her sister stole by getting married.
The dog outsmarted her. I just hope it can find a good home.