First of all, NOBODY gets to inherit anybody else's federal pension ~ not even a spouse. However, a pensioner can forego 10% of his pension to set up a dependent's annuity which will pay up to 55% of the normal amount of the pension.
However, the only people who can qualify are spouse, former spouse, dependent child, and, or a retarded or disabled child (of any age) ~ and if the pensioner doesn't do that these people GET NOTHING.
One slight caveat. If the federal employee dies on the job, then his wife does "inherit" his pension.