Is it permissible to take from relatives' Zakat for marriage and to buy a house, given that there are savings that are insufficient to do so without incurring debt?

It is permissible to use Zakat to cover the costs of marriage and housing for those who do not possess sufficient funds for them. It is also permissible to spend Zakat on the education of siblings if they are successful in their studies of knowledge needed by Muslims, and they cannot earn or combine earning with studying.