My husband wkd for huges aircraft '77, where can i get info on his benefits.?

he paid for insurance so i would get 80% of his pay when he died. but when he died in '78 they said i couldn't get it because i got too much from ssi (children/widow beneifts). i'm trying to find out what insurance company he was paying into and see if i can collect on that now that i'm retiring. i called ratheon and they can't find his files. thanks. cindy moore southern cal