Am I, the borrower, more entitled to the money that fell from the deceased, which was part of a loan, or are his heirs?

The ruling is based on the agreement between you and your friend. If you asked him to borrow from the bank to lend you the amount, then the transaction between him and the bank is specific to him, and your debt remains due to the heirs, and the bank's waiver of his debt does not affect the deceased. However, if the agreement between you was that he would borrow for you from the bank in his name merely as an agent on your behalf, then the loan is for you, and your friend is merely an agent and guarantor. The waiver of debt from the guarantor does not waive it from the principal, and the bank's debt remains your responsibility to pay to the bank, not to the heirs of the deceased. In both scenarios, the debt is not waived from you unless the bank explicitly waives it from you in the second scenario.