What is the ruling on a mother supplicating against her son? Will it be answered if the reason for it was a condition or anger? And can lack of success in exams be due to that?

A mother's supplication against her child is answered, but God's mercy dictates that prayers uttered unintentionally in a state of anger are not answered, as Allah Almighty says: "And if Allah were to hasten for the people the evil [they invoke] as He hastens for them the good, their term would have been concluded for them." Nevertheless, the Prophet forbade supplicating against children so as not to coincide with an hour of answered prayers. Therefore, one must be cautious of angering one's mother and be diligent in honoring and obeying her, for her right is immense. If you fulfill your duty towards her, then her anger or her unjust supplication will not harm you.