All things aside, I just find it creepy to conceive a child with your dead spouse. I don't think I'd be ok with knowing that my dad died years before my birth. It would just not be OK with me.
So this mom has three kids - biological or step with her husband. He passes away. She uses his frozen sperm to become pregnant. Conceives twins. Has them. Petitions the Social Security for survivor's benefits. Is denied.