What is the ruling on mortgaging a house for someone who cannot afford to buy it, and is this considered usury? What is the ruling on it in a case of necessity?

The aforementioned transaction—lending a sum of money in exchange for renting the borrower's house to the lender at a reduced rent—is considered a loan that draws benefit, which is one of the prohibited forms of usury (riba). Similarly, if the situation is reversed, where the homeowner mortgages his house to the lender for the lender's benefit, it is also unlawful. As for necessity, it is to be considered: if a person cannot find shelter for himself and his family except through this method, then it is permissible for him until the necessity ceases. However, if he can obtain housing through lawful means, it is not permissible for him to resort to what is forbidden.