Is it permissible to give the monthly charity in the form of tuition fees for a Quran class for my younger sister, so that she may memorize and learn the Quran, knowing that she is my sister?

Voluntary charity (Sadaqat al-Tatawwu’) may be given in anything that is beneficial, and to anyone; and it is better to give it to relatives and kin, especially if they are in need, for the Prophet, peace and blessings be upon him, said: "Charity given to a poor person is charity, and to a relative it is two: charity and upholding the ties of kinship." Charity can be in anything permissible from which the recipient benefits, for the Prophet, peace and blessings be upon him, said: "Every good deed is charity."