She may be bored or possibly hungry..Maybe keeping something simple for her to chew that won't choke her will be beneficial..Little Marshmellows would be great..
Or it might just be a new habit she has developed..
My sister use to pick her bedspread apart by pulling any thread and keeping it going..It frustrated her to not be able to do this..So it could be that your mom needs something to just keep her hands busy..I wonder if the childrens counter would be good for her? It would keep her hands busy..The counter I see is the one where the beads go side to side..
There always seems tobe possiblilites..I hope you can find a trick that helps her..kd