Oh god I can feel the hopelessness of this situation even though it's just a manga. Since the horned kids definitely won't let him have an easy death if he gets found out. The author cooked with this setting.
The mom does not have a reason to act like this, she acting like a bitch by her own will. Unlike the father who seems like he is doing it to stop some tome game villainess banishment scenario.
Why do I got a feeling the queen is trying to bring down the house of lord faction cuz of that flash back she had; where she was looking at the late queen and king, and she smiled in that flashback