Hello. My father was a state (of Massachusetts) employee for 40 years and therefore eligible for a state pension upon retirement. My mother was an elementary school teacher for 30 years (in Mass as well), and also eligible for a pension. Both my parents retired in 1994 and began collecting their pensions. My father also had enough quarters paid into Social Security to qualify for a small monthly benefit, which he collected in addition to his pension. My father died in 2013 at the age of 87. As his surviving widow, my mother was eligible to collect 2/3 of his state pension which she has been doing since his death. Naturally, she continues to collect her own teacher's pension as well. Is she also eligible to collect either all or part of my father's social security benefit? Immediately after my father's death I was told "no" in answer to this question by someone on the phone at Social Security. Since then, other friends and co-workers have told me that my mother is being short-changed and is indeed eligible to collect something from my father's social security. Who is right? (my mother is currently 87 years of age).
Due to the Government Pension Offset (GPO) provision, your mother's potential widow's benefit would likely be offset by 2/3rds of the amount of her teacher's pension (https://www.ssa.gov/pubs/EN-05-10007.pdf). When I state that, I'm assuming that her earnings as a teacher were exempt from Social Security taxes.
So, whether or not your mother could receive a widow's benefit from Social Security depends on the amount of her potential widow's benefit, and the amount of her teacher's pension. The surest way to find out if she is eligible would be to file an application for widow's benefits with Social Security. The worst that could happen is that they will inform her that no benefits are payable.