now the IRS has a EIN to match to return.  This is why I would file and mark final so to satisfy the filing

The IRS also has an SSN to match to a name.  They could have been tracking it for the last 20 years, and when it drops off someone else's return as a dependent they might wonder why it has not been filing its own return.  So, everyone should file a return, even if they don't have any income, just in case IRS asks.