I HAVE SOME GIRL TROUBLE? ?

So, my friend has a problem. He's in Nebraska and his girlfriend is kinda still in Houston. He's coming back in July, but he saw on another boys Facebook that the other boy, named Jose, was hanging out with her. And calling her "princess." I'm saying that he should break up with her. And drop that Jose ************, and be done with it. But he's still in love with her. What should he do? From someone elses point of view.