What is the ruling if two out of three brothers admit a debt owed by their deceased father?

Primary text

If two out of three brothers, who are trustworthy, admit a debt and testify to it, their testimony is accepted, and the remaining portion of the debt is established against the denying brother. This view is held by Al-Hasan, Al-Sha'bi, Al-Shafi'i, and Ibn Al-Mundhir.