Is the loan amount for which my father was a guarantor to my uncle considered a debt owed by my deceased father after my uncle's death and his renunciation of his assets to his wife, who did not repay the loan? And is it obligatory to repay this debt despite the case being settled with my father not inheriting any estate?

The uncle's heirs must pay the debt to the bank before dividing the inheritance to clear the liability of both the uncle and the father. If the uncle's heirs refuse to pay, and the father has a hidden inheritance, the debt must be paid from it, and then the father's heirs can claim reimbursement from the uncle's heirs. The bank has the right to demand payment from the guarantor, whether alive or deceased. If the father did not leave an inheritance and the bank absolved him, his liability is cleared. However, absolving the father does not waive the debt from the uncle. Sons are not obligated to pay their father's debt from their private funds, but paying it as a donation is considered an act of kindness and filial piety.