Need to cancel gift deed done in favour of nephew and niece

Dear Sir, We have an issue, my aunt called my mother stating that her own land and my mother's land are nearby and both lands are filled with ditches and have no value. and once the property is sold out the money will be divided accordingly. my mother believed blindly and also took me (I am her son working in Pvt company aged 36 years) as a witness and executed the sale deed. Later when we asked for money, my aunt told me that my mother has executed a gift deed in favor of her nephew and niece. We requested them to reverse this but they are not ready. We have now filed a civil suit against them within 6 months of execution in 2021 My mother, and father are alive and we are 4 kids. (2 brothers and 2 sisters and all married) Now in 2021 we came to know that even earlier they have executed similar gift deeds and general power of attorney in favor of their name. Sir, please help us with how to challenge here as the gift deed was executed in a completely fraud manner. We are already in debt of 20 lakhs with different banks because of our financial issue and here they have taken the benefit of our lands Seeking advice