Is it permissible to give zakat to the wife's sister whose husband is experiencing financial hardship and has lost his job, knowing that they own a property they do not wish to sell because it is allocated for their daughters' future marriages?

Zakat is not permissible for your sister-in-law, who is married to a man who owns a property that would cover their basic needs if sold, because the Prophet, peace and blessings be upon him, said: "Charity is not permissible for the rich." The matter of their daughters' marriage is left to Allah. However, if the husband is unable to earn, and the rent from the property does not cover their needs, then it is permissible to give them from Zakat to complete their needs. They can also be assisted with a loan, a gift, or voluntary charity.