Is my sister entitled to her husband's retirement pension/ savings?

My sister is a goodhearted nurse and mother of four (one who died at age eight), and married to a psychological abuser for 27 years. He waited until our mother died suddenly, and our father was actively dying to sue for divorce, and threatened her with " If you try to take any of my savings or retirement, I will make you homeless". She was scared and very emotionally vulnerable, and her own lawyer may have been sick at the time because he died right after the divorce. Her Ex left her with ALL the credit card debt, parent education loans for their sons, both mortgages on the house, and he walked away debt free. He kept many thousands in savings (earned and saved during their marriage)and all of his retirement benefits. She has been struggling horribly ever since. She is employed, but 60 years old and horribly in debt. Can her divorce be renegotiated? She is afraid to contact a lawyer to find out because she's afraid she can't afford it.