Wait, I reread and you are saying that she isn't cooperating and staying quiet for the entire five minutes? The good thing about five year olds is they 'generally' cann't tell time, so if it has been a 'significant amount of time being quiet, you as a parent can 'say' its been five minutes even I not.

I say though, time out isn't supposed to be a punishment. It is supposed to be time to calm and reflect. So what (if anything) is your hubby hoping to achieve with timeout? It sounds like he is just a little misguided on what it's purpose is.