Faulty Memory

What do you do when your mom insists her mom is still alive, after her death 24 years ago. She says she sees her periodically and that my dad has just hidden her somewhere? I've tried everything I can think of but she is adamant. They even put flowers on the graves today and she insisted Grammie wasn't in hers. I guess the good news is this is the only dead person she vows is still alive. The way she is talking about her all the time is creeping me out.

I tell myself maybe she just feels her spirit very strongly but her newest one was she said she saw her at a baby shower. I think Mother is living in a different world, even an alternative universe.