The filial privilege rule is not strictly a rule on disqualification because a descendant is not incompetent or disqualified to testify against an ascendant. The rule refers to a privilege not to testify, which can be invoked or waived like other privileges. 
Facts:

Larry Erguiza was charged with one count of rape. The victim’s father, testified that the family of Erguiza went to their house after the case was filed, and  initially offered P50,000 and later P150,000. Albina, the mother of Erguiza admitted that she did talk with the parents of the victim, but according to her, it was the spouses who asked for P1M, later reduced to P250,000, to settle the case and that she made a counter-offer of P5,000.00.


 Issue:

Can the offer of compromise given by the mother of the accused be used as evidence of his guilt? 


Held:

No. The alleged offer of the parents of appellant to settle the case cannot be used against appellant as evidence of his guilt. Appellant testified that he did not ask his parents to settle the case. Moreover, appellant was not present when the offer to settle was allegedly made.

An offer of compromise from an unauthorized person cannot amount to an admission of the party himself. Although the Court has held in some cases that an attempt of the parents of the accused to settle the case is an implied admission of guilt, we believe that the better rule is that for a compromise to amount to an implied admission of guilt, the accused should have been present or at least authorized the proposed compromise. Moreover, it has been held that where the accused was not present at the time the offer for monetary consideration was made, such offer of compromise would not save the day for the prosecution. (People vs. Erguiza, G.R. No. 171348, November 26, 2008)