Whatever distinction you're trying to draw with the comments about revocable vs irrevocable isn't relevant, IMHO - or if it is relevant, I don't understand what you're getting at.

A grantor trust that is revocable during life becomes Irrevocable upon death and is reported as a trust on the 1041.  It seemed to me that is this is true by law but is filed as an estate on the 1041 because the grantor died.   I need to understand why a trust remains a trust after death of the grantor.

My goal is to be able to have a FYE of 2/29/24 for the tax deferral. Since the 11/30 deadline passed this is not an option.  I can explain this to my client.

Thank you for your time.