The 4 wheel drive of a Subaru would be nice for getting through snow. She does not need anything as large as a Forester. An Impreza would be a good choice.
You are going to have to school her on the fact that if one tire ever gets damaged to the point that it has to be replaced, she has to replace all 4 at once. Also, be sure to have her rotate the tires, like every oil change.