Passports
Return or cancel with the US Department of State guidance; keep copies for estate records
Some steps differ by region inside the country.
Where
The US Department of State passport office, by mail.
How
Locate the passport in their files or safe, and note the number before sending it anywhere.
Mail the passport with a certified death certificate and a letter asking for it to be canceled.
Ask specifically for the canceled passport to be returned if the family wants to keep it.
Deal with any Global Entry or trusted traveler membership separately.
What to bring
The passport
A certified copy of the death certificate
A signed letter requesting cancellation and return
Sources
This is practical information, not legal, medical, or financial advice.