ANSWER:
Your mother is transgressing against your wife and she has no power or control over her. It is obvious she wants to enslave her.
If you are a real man, you should protect your wife from such aggression and pay no attention to what your mother is ordering you to do, while being respectful and dutiful to her at the same time.
Her curses have no value and Allah doesn’t listen to them!
If she orders you to kill someone or curse you, what would you choose?