Is it permissible to give Zakat al-Fitr to needy half-siblings after the father's death?

Zakat al-Fitr is given to the poor and needy, and a poor relative has a greater right to it. It is not permissible to give zakat to someone whose maintenance is obligatory upon you, unless you are unable to provide for them. If you are an heir to them, it is not permissible to give them zakat, unless you are unable to provide for them due to your limited funds, in which case it is permissible. If you are an heir to some of them but not others, give the zakat to those from whom you do not inherit.