Cancellation of gift deed - Defence for the respondent son ?

Mother doctors a situation where first she gets the son to execute a registered gift deed in the year 2016, of his self acquired property in favour her daughter then about an year leter, in the year 2017 the mother executes a gift deed of her share in her father's ancestral property in favour of her son where the son invests INR 30 lakhs for construction of a house, the mother cunningly waits from 2017 till the end of 2019 until the construction is over and then with the help of her daughter, files a petition under the provision of Maintenance of Senior citizens act, 2007 making false aquisitions against the son and seeking the Court to cancel the registered gift deed executed in favour of the son in the year 2017. What would the son need to do for defending himself ? What legal remidies are avaliable for defence for the son who has to protect his honour and self esteem and also what action can the son take against the unscrupulous daughter (sister) and the evil minded mother. Please advise