What is the extent of permissibility for an elderly woman over eighty years of age to lighten her clothing, according to those who say that the hijab does not include the face and hands?

If a Muslim woman reaches an age where men no longer desire her, it is permissible for her to remove in front of non-mahram men what is above her chemise and head covering, such as an abaya and jilbab. As for the chemise and head covering, it is not permissible for her to remove them, because that would expose her 'awrah.