I am sorry for your loss.
No, I disagree. Your mother is not the nominee, you and your brother are the nominees.
Your mother was the original owner of the account. Since the brokerage company liquidated the account to her two sons at death, then you will need to split everything up between the 3 of you.
Since the Combined 1099 was issued in your mother's ssn, then you will either report everything on the Combined 1099 in her return and then "nominee out" the portions belonging to yourself and your brother by listed a line item on each type of 1099 called Nominee distributions and subtracting out the amounts belonging to others after her death.
Then, you and your brother will need to claim your halves of the amounts nominee'd out of her return into your own returns.
Otherwise, you can break it all down by paper and report only the portion belonging to your mother before death on her return and then each of you brothers will split the remaining portions on your own individual income tax returns.
Your mother is NOT the nominee because the 1099 combined docs came in her name and ssn. You and your brother are the nominees because you did not receive a combined 1099 in your names and ssns even though you do each need to claim your share on your own return.
Some people prefer to create the two sets of 1099s for the nominees from your mother's ssn, but that is not necessary as long as you keep records in case IRS later sends a letter of inquiry.
There is no need to create a 1099-div for your deceased mother, she already has one..
For additional information, please refer to the following:
How to handle Death in the Family on the tax return
[Edited 03/02/2021|3:50 pm pst]
