Oh my goodness ... unless you want to be seen as the MIL from "HE double hockey sticks", then shhh!!
She's at a different stage in life and has different interests. Her non-productivity, as you mentioned (different words), may be her way of relaxing, whereas for you, it's sewing.
For now, she may only see the sewing machine as a means to an end for mending. Give her some time and space, and perhaps with that time, you'll see her start to be interested in what you are doing. There may be a specific quilt that will catch her eye, and she'll be begging for you to help her!
We can't "make" anyone do anything ... they have to have the "want".
I know this may be an exercise in frustration for you ... think of all the patience you can master along the way!
Good Luck!