Mother given all money to sister and her husband what to do

Family has four daughters and only son along with mother and father. mother and son jointly own a house from father's income. after 5 years son transfer his 50% share in favour of mother. same year mother sold that property and gift the entire money to the spouse of her youngest daughter, who bought a new house of that receipts in his own name. can other daughters claim for their share ? is gift from mother in law to son in law exempted from gift.