If the housing loan is the same, the loan is not in the Housing Authority. They all go to the bank to sign the loan contract first, and the bank evaluates that the loan is ok before transferring the ownership. After the house is closed, you put the house in the bank, and the bank transfers the loan to the landlord. Of course, you must pay the landlord a down payment other than the loan before the transfer. Of course, you must sign a sales agreement between you.

If the landlord is worried, then find an intermediary company he trusts to give them some money as an intermediary and use an intermediary contract.