The legal process for the scenario you've described to evict or remove this adult
child from your home is very likely the same as would be required of any other
landlord with respect to an intransigent tenant which means that you'll need to visit
the clerk's office of your local general district court (civil division) to begin filing
the paperwork for what the law refers to as an Unlawful Detainer action to evict
this person from your home.
The legal process for the scenario you've described to evict or remove this adult
child from your home is very likely the same as would be required of any other
landlord with respect to an intransigent tenant which means that you'll need to visit
the clerk's office of your local general district court (civil division) to begin filing
the paperwork for what the law refers to as an Unlawful Detainer action to evict
this person from your home.