Is it permissible to give zakat to a indebted woman who is unable to pay her mortgage, knowing that her husband wants to give her from his zakat for the same purpose, taking into account that the apartment is mortgaged to a usurious bank?

It is permissible for the landlord to take a pledge to guarantee against any damage the tenant might cause, but it is forbidden for him to benefit from this pledge. So, if the woman benefited from the pledged money and spent it, this is a forbidden act, and she should not be given from zakat to pay off her debt unless she repents. If she repents, it is permissible to give her from the share of al-gharimin (those in debt).

It is permissible for a husband to give his zakat to his wife if she is in debt, because he is not obligated to pay off her debt.