Answer
(Fatwa: 1479/2007/D=1433)
If your sister is not sahib nisab rather she is poor and entitled to receive zakah and she is not a Sayyid then you may give your zakah money to her, no matter if her husband is a Sayyid while you will be giving to your sister. If the jewelleries which are kept to give to daughters are in the possession of her husband or it has been given in the possession of the daughters and they have been made its owner then the ruling of giving zakah to your sister is the same which we mentioned above. But if the jewelleries are in the possession of your sister then you cannot give your zakah to her (sister).
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband