Can the buyer back out of purchasing an apartment to avoid usury after paying a down payment, taking into account his mother's health conditions, given that she shared in paying the down payment, and seeking legitimate solutions that satisfy both parties?

It is permissible to purchase an apartment through Murabaha with the bank, provided that the bank first buys and takes possession of it, then sells it to you, and that the contract is free of any late payment penalty clauses.

Any prior contract between the client and the contractor must be terminated before the bank enters into the purchase process, and the contract concluded between the client and the contractor may not be transferred to the bank.

The acceptable scenario for the transaction is for the contractor to refund the deposit to the client upon signing the assignment contract.

If the transaction with the contractor is terminated, it is permissible to deal with the bank, but it is not permissible to take a serious margin in a Murabaha sale before the bank owns the commodity.