Yes, they already made an in person update at a Nexus Enrollment Office, albeit one staffed only by CBSA. The question is whether that information has been updated on the US side or if a second visit to a CBP ​​​​​is also needed.

If the change is already reflected in TTP, it means that the Canadian enrollment centre passed the info on to the US already, which is why I suggested they check their account to see.

Not out of the question for the information to be shared, during the pandemic when all the Nexus enrollment centres were closed my wife did a name change and passport update at the GE Enrollment Centre at BOS - we never reported it separately to CBSA.

Unfortunately this new arrangement for Nexus enrollment centres is not the friendliest for people who just need to make information updates.