I think she's entitled to 1/2 your father's SS pay by default (if they were married more than 10 years). Not sure if you have to ask for this specifically. If the divorce decree doesn't specifically state 1/2 the retirement money, I believe she could get a lawyer to get this enacted for her. I think she would be entitled to it. She could just try first on her own to get the retirement benefits (less costly than a lawyer).