POA expires when the principal dies.  How do you know the return has not been processed -- is a refund expected?  

I client who filed in March 2020 died in June 2020.  No refund yet issued, but IRS asked for a Form 1310 a few months ago.  Meanwhile the 2021 return, filed with a 1310 in March 2021, was refunded in October.

I think the SSN is locked fairly quickly after death.