Well If I were you I would teach him to treat all girls with respect. So yes if he asked her out to the movies or dinner he needs to pay ALWAYS! Just think back to when you were dating. I know for me if a guy took me to the movies but then expected me to pay my own way I would have been pissed! It's one thing if hes just out with a big group of kids and they all go grab a bite then no he doesn't have to pay for any of the girls there but if it's a real date then yes he should pay. And he should still open doors for her, walk her to her door
etc. I know times are different and keep changing but I am only 28 and I still remember boys doing this stuff for me back when I was a teen so I know this isn't way out of the ordinary.