Is the testimony of two people valid regarding the divorce of their mother's co-wife?

Primary text

The testimony of two witnesses regarding the divorce of the wife of their mother's husband is accepted. This acceptance holds whether the person witnessed divorcing (the *mashhud alayhi*) is their father or a stranger. The acceptance is based on the fact that their mother's right is not increased or affected by this testimony. The consideration that accepting the testimony might increase their inheritance does not prevent its acceptance, as evidenced by the acceptance of a legal heir's testimony concerning the estate of their deceased relative.