Can child claim for money from divorcee Mother

My cousin sister, she's undergoing mutual divorce under hindu marriage act. She's has 7 years old son. But due to fights and seeing future, she's has handed over custody to sons father. This guy is very clever n cunning. In mutual divorce also that Man has asked my cousin to bear all educational expenses of their son till age of 18 years. She's ready to give this expense to her kid as she's serving in semi govt organization. But my question is what if her son would file a case against my cousin for any share of property or bank balance? Already she will be bearing all his educational expenses till 18. So what we can do if that son reaches 18 years of age n with influence of his father, he may file case in court for asking more money in property or bank balance. Is there any way to sort out this issue?? To be safe from this issue?? Kindly let me know please