there is no sin for such elderly women as are past the age of marriage if they lay aside their outer graments provided that they do not mean to display their adornment. nevertheless if they behave modestly it would be better for them for allah hears everything and knows everything.
والقواعد من النساء اللاتي لا يرجون نكاحا فليس عليهن جناح أن يضعن ثيابهن غير متبرجات بزينة وأن يستعففن خير لهن والله سميع عليم