Hindu Matrimony - Step mother separation without divorce

My father has been made to marry girl(my Stepmother) , few months after my mother expired when she was 32. I was 7 years old that time. However my father could not forget my mother, he could not with 2ndwife. Hence my step mother left house within few months. They did not apply for divorce neither contacted legally. My step mother married another guy after few months. now its been 20 years. She is in financial problem. we got to know that she is trying to put case on my father for property. Kindly suggest if she is eligible to apply for property after marrying another guy?