Making a Will is the way parents can divide their assets fairly among economically unequal heirs

Parents often fear exercising authority over their own wealth, especially when they feel one child deserves a bigger share of the legacy than the others, because of the repercussions of such a move. For example, in one case the eldest son spent all his earnings supporting widowed mother and two younger sisters. He is now left with little savings so the mother wants to will the house to him but the daughters want their share. What to do?