Retirement benefits in tax return (itr-2)

The Question of including these in your mother's return ( assuming she has her own independent income subject to tax) does not arise at all, as these are technically income of your late father and your mother is only in a representative capacity to file your father's return. Howeverf your father's income has to be computed including the salary upto date of death, any retirement benefits received which are taxable, and if the same is more than 200000/- then your mother has to file a return in a representative capacity including the above exempt items also.