Of course he does. He's a ghost, it's possible there are things he knows of your life you never would have told him.
[Eponine]
What? Does that mean...?
Well. I can see where the idea comes from. The two of you do spend a considerable amount of time together. But it certainly doesn't mean you've up and replaced Marius in your heart, or have chosen to spend time with him simply because he's a student, too. You're from the same time, and the same place, of course you'd gravitate to him.