How do you cash a 1940 penny policy?

my granny took out four penny insurance policies for each of her four daughters to mature when they reached 75 or died.my mother has now reached 75 and tried to find out what she would be due from the prudential they have told her as granny took out the policies it was her money and would have to be divided between the four of them but they all have their own policies and as my youngest aunt has 13 yrs to go till then my mother is not pleased as she sees this as her money as they have their own policies and she could be dead by then especially as this was her funeral money as she puts it so be warned