If the first wife is alive, and with consent of the first wife the husband married the second wife, and the second wife non other than the own sister of the first wife, after the death of the husband whether the second wife and her children having right on the pension and service benefits are nnot ?

The Second Wife has no right at all in the husband's death benefits or pension.  However, the children of the second wife has right over all the separate  properties of the husband including death benefits and pension .