Praise be to Allaah.
Zakaat al-fitr is to be given to the poor and needy, because
Ibn ‘Abbaas (may Allaah be pleased with him) said: The Messenger of Allaah
(peace and blessings of Allaah be upon him) enjoined zakaat al-fitr as
a purification for the fasting person from idle talk and obscene speech, and
to feed the poor. Narrated by Abu Dawood (1609) and classed as hasan by
al-Nawawi in al-Majmoo’ (6/126) and by al-Albaani in Saheeh Abi
Dawood.
If your wife’s family are poor and needy then there is
nothing wrong with giving zakaat al-fitr to them, rather it is better to
give it to them than to anyone else, because the wife’s family (in-laws)
have the right to be taken care of as part of honouring one’s wife and
treating her kindly.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said in
Noor ‘ala al-Darb (682):
Undoubtedly the in-laws have rights that no one else has who
is not an in-law. End quote.
We hope that Allaah will decree for you the reward for
charity and the reward for taking care of your in-laws and treating your
wife’s family kindly.
And Allaah knows best.