Hi @janetteallan​
I'm sorry to hear about the internal conflict there (kidding, of course).
LastPass does not have the ability to force an override of competing password managers, however you can easily log off of Nordpass in order to disable it, or make your default web browser something other than the family member.
I know the Enterprise version of Chrome can disable extensions based upon the user that is logged in, but I'm not sure about personal versions.