Column of the Week: Wills

Dear Len & Rosie,

I made a new will after my husband died ten years ago. I had five children, and my will divides my estate among them equally. Four years ago, my son Richard died. He had two children, and a wife, an awful woman named Margaret. There is no love lost between us. I want to make sure that she gets nothing when I die. Do I need a new will?