After she graduated university, she returned to the Bronx apartment she lived in at age five.
Sounds like her family was running a sublet scam for twenty years on a rent controlled apartment.
Not sure what you think was a scam. It’s legal to sublet a controlled apartment, with the landlord’s permission, and it’s also legal for adult offspring to move in with their parents.
There are plenty of scams but you haven’t mentioned one.