Urgent help please !

Dear Team CC Members !
If an Individual dies before filing the return of Income (covered under 44AB) and when his Return is going to be submitted by his son, he has to sign digitally. But PAN mismatch is happening when compared with DSC encrypted PAN (Son) and logged in PAN (Deceased father). Unable to change the PAN in the field mentioned in the "Update your D.S.C." in the e-filing website. It is showing Logged in Person's PAN and not allwoing to change.
Please suggest the way out if any if the same thing comes to your notice.