I read it as the victim’s son, not hers.
It’s an “honor” thing in Muslim law. The temporary husband attended the hanging, and the stepson got to pull the chair out from under her.
Family males are expected to inflict justice on family females under sharia law. That’s why it’s the father and brothers who cut off their daughter or sister’s head if she is raped—to repair the family honor.
Sorry. I should have put the “/s” after the son remark. I was being sarcastic as to who was the victim.