It wasn't that they didn't have life insurance at all. It was that they couldn't increase their life insurance on the private market either due to their line of work or "Act of God"-style clauses. Or at least they thought that to be the case. This is similar to how some life insurance policies exclude death while acting as a pilot in general aviation.

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.