Is the testimony of a son for his mother accepted if he dies after giving the testimony and before the case is concluded, while his mother is still alive?

A child's testimony for their mother is not accepted due to the accusation (of bias) it entails, just as the Mudawwanah (Moroccan Family Code) stipulates that the testimony of parents, or one of them, for their child is not permissible, nor is the child's testimony for them, nor is the testimony of one spouse for the other.