20 CFR 404.339 - How do I become entitled to mother's or father's benefits as a surviving spouse?
You may be entitled as the widow or widower to mother's or father's benefits on the earnings record of someone who was fully or currently insured when he or she died. You are entitled to these benefits if -
(c) You are unmarried;
(e) You have in your care the insured's child who is entitled to child's benefits and he or she is under 16 years old or is disabled. Sections 404.348 and 404.349 describe when a child is in your care.