Ancestry/Genealogy

The estate attorney just cares about the actual death verification.
They may not even check to see if birth data is correct.

Even if they do check, death certs often have incorrect birth info, or even marriage info.
But usually the address, date of death, reason for death are typically correct.
And that is what the attorney is looking for.

The social security info may be correct because your mother herself filled out those forms
when she applied for social security benefits. And the federal death index just took the information off the death cert your brother filled out.

My brother would probably screw up a death certificate too if it is any consolation.

You can contact the state to see if with proper documentation you can obtain a corrected death certificate.