25 March 2013
Yes, you can file. But while filling of IT return select "return filing under representative assessee" and fill the details of representative assessee like his/her pan no and name etc... what they required. As well as at the verification details please fill the details of representative assessee who signing the ITR and submitting like his name, his father's name and his PAN no.
26 March 2013
Same procedure except the ITR will be sumit to the IT office in Hard copy. Along with the return form submit a letter indicating expiry of the assessee with enclosure of Copy of death certificate.