Can a person give Zakah to his sister? To whom can Zakah and Fitra be given?

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
There is no harm in a man or a woman giving his/her Zakah to his/her brother/sister if the latter is needy or poor. In fact, giving Zakah to such recipients includes yet another good deed which is helping needy or poor relatives. But it is unlawful to give Zakah to the father, grand-fathers, mother, grand-mothers, children or grand children no matter how needy or poor they are. Since he is obligated to spend of his wealth on persons in this category, the money spent on them cannot be considered as Zakah. For him to consider any portion of such money as Zakah would be as though he was denying a rightful portion of his wealth, on which Zakah is due, from the poor.
Allah knows best.