Is it necessary to cleanse a copy of the Qur'an that a sister touched after scratching her skin, especially a sensitive area, during sleep, given that she was not conscious of what she was doing?

A sister touching her body during sleep does not indicate her lack of caution regarding impurities, as a sleeping person is not religiously accountable for their actions, according to the Hadith: "The pen has been lifted from three..." Your sister's hand is pure, and its impurity is not determined merely by doubt. The principle is that doubt does not affect the certainty of purity. Therefore, you are not required to purify the Mus'haf that your sister touched, as it has not become impure. It is forbidden for someone who is not in a state of Wudu' to touch the complete Mus'haf. However, it is permissible for a teacher or a student to touch a part of it without Wudu'.