I used to hoard a bit as a child. My parents curbed it for me by strictly enforcing that the "hoarding bags" stayed in my closet, where i could find them. that way i couldn't hide food in them as easily. Perhaps the drawer where she was placing her cat could be her, "secret stash" and so long as it doesn't exceed the drawer, and there is no food, then she can have whatever she wants in there. Not sure if it will work for you, but it helped me.