In which head income charged

Dear Sir, After death of a central govt/state govt empolyee his wife will get half pension as per norms. His pension is taxable and he file his return ITR 1 in salary head. After death his wife is getting this pension now this is taxable in her hand also. 1). Then now can his wife filling this return in her own name after registration of her PAN card? 2). If he will filling her return then in which head she will show his income, salary or other? Please clarify me the tax treatment.