You need to change the policy into her name. We've had cases like this - don't know the exact mechanics of it, but obviously the policyholder should be the main user of the vehicle, so if he no longer has a licence, this is not the case.
We would not cover any accident she would have if the policy was still in his name but he did not have a licence (apart from our road traffic act responsibilities).
We had a case where the policyholder was blind (!) but his sons had used him to take out the policy to get a cheaper premium - obviously this is not the case here, but we refused to indemnify the claim they had.
Hope that makes sense!