What is the ruling when one of two heirs admits a debt owed by the deceased father, amounting to half of the estate, to a third party?

Primary text

If a man leaves two sons and two hundred dirhams, and one son admits a debt of one hundred dirhams owed by his father to a stranger, the creditor receives half of what is in the admitting son's inheritance share. The admitting son is only bound by the debt to the extent of his inheritance share, which is half of the debt, i.e., fifty dirhams. The remaining fifty dirhams are covered by his testimony concerning his brother. If the admitting son is trustworthy ('adl), the creditor has the option to swear an oath alongside the son's testimony and claim the full hundred dirhams. This is because the son's testimony does not present a conflict of interest, as he draws no benefit nor averts harm to himself through this testimony. The supporting scholars for this view are Al-Hasan, Al-Sha'bi, Al-Shafi'i, and Ibn Al-Mundhir.