"The Apollo insurance covers are autographed postal covers signed by the astronaut crews prior to their mission. The primary motivation behind this action was the refusal of life insurance companies to provide coverage for the astronauts. Consequently, the astronauts devised a strategy involving the signing of hundreds of postal covers. These were to be left behind for their families, who could then sell them in the event of the astronauts' deaths.[1] The insurance covers began with Apollo 11 and ended with Apollo 16."
AFAIK all of them were former military and obviously current government employees so their families would have been entitled to any military life insurance they purchased as well as any pension benefits due (military and federal civilian). I can't give you the exact amounts because it has changed over the years and also depends on how many years of military and/or civilian service you had.
But generally all government employees covered under the retirement plan have an annuity or monthly survivor benefit available that is some portion of their final salary at death or their average salary whichever was higher. Often there is a fixed adder as well (basic death benefit adder right now is $41,000 per year so your spouse would get 50% of your final salary plus $41k).
In addition the federal plan (and social security) pays monthly for surviving children until they reach age 18. The federal plan is a bit nicer in that it pays until 18 or 22 if you are a full time student. Both pay for life if the child is disabled (though the government definition of disabled is rather strict).
All of this is just survivor benefits. Once your surviving spouse retires they are entitled to the pension payments you would have received.
As far as I know all of the astronauts were military at that time, so they probably would have been covered by this program. There could be any number of nuances I'm not aware of though.
[1]https://benefits.va.gov/benefits/infographics/pdfs/timeline_...