Short answer. Yes. Article 2069 of the Civil Code lets a guarantor who paid a time-bound debt before it fell due demand reimbursement immediately, without waiting for the original due date, once the debtor has ratified that early payment. Ratification removes the very reason the law normally makes the guarantor wait.
What the law says
If the debt was for a period and the guarantor paid it before it became due, he cannot demand reimbursement of the debtor until the expiration of the period unless the payment has been ratified by the debtor.
Civil Code, Article 2069 — Premature Payment by the Guarantor. Read the full provision →
The default rule: an early-paying guarantor waits
Article 2069 states the general rule plainly: If the debt was for a period and the guarantor paid it before it became due, he cannot demand reimbursement of the debtor until the expiration of the period unless the payment has been ratified by the debtor. As a guarantor, paying the creditor ahead of schedule is your choice, but it does not automatically shift the timetable onto the debtor. Without more, you would have to wait until the original due date arrives before demanding reimbursement, exactly as if the debtor had been the one paying on time.
Why the law holds the debtor to the original date
The debt was for a period for a reason — the debtor may have arranged funds, income, or other obligations around that due date. Letting a guarantor's unilateral decision to pay early force immediate reimbursement would strip the debtor of the benefit of the term he originally bargained for, even though he did nothing wrong and was not consulted about the early payment. Article 2069 protects that arrangement by default, regardless of how well-intentioned the guarantor's early payment was.
Ratification is what changes the timeline
The article carves out exactly one exception: unless the payment has been ratified by the debtor. Once the debtor ratifies — that is, approves or adopts the early payment as something done on his behalf and with his sanction — the reason for making the guarantor wait no longer applies. Ratification is treated as if the debtor himself had authorized the early payment from the start, which is why it lets you demand reimbursement right away instead of at the original due date.
What this means for you
Since your borrower has already approved of the early payment, Article 2069's exception is what you can rely on: you are no longer bound by the original due date and may demand reimbursement now. The article does not spell out a required form for ratification, so if there is any doubt about whether the debtor's approval is clear and unequivocal, having it confirmed in writing will make your demand for immediate reimbursement easier to support if it is ever questioned.