Death of assessee

can any one plz help me !

acutally i have one doubt! If one of the assessee had died recently he was a senior citizen, his turnover exceeds 60 lakhs. while filing of his IT return. i have one doubt who has to sign the return, and whose digital signature should be taken. how to mention the same in the return! and what documents should carry the CA to sign the papers.

pls clarify!