Charginig your adult child rent?
I have told my daughter that when she goes to college she can live here rent free. I don't want her to have to worry about bills on top of school, I want her to concentrate on her studies. Now, if she wants the extras then she will need to work. I will keep a roof over her head and food in her belly though.
Ed was brought up the same way but he worked anyway because he was always buying himself cars and projects, so I'm pretty sure Charlie will be the same way. As long as he's in school and doing well he doesn't have to worry about rent.