Why would he text a lot but not contribute much in person?

Why would you be into regularly texting and being proactive about it, but not engage much during an actual face-to-face conversation with someone? There's a guy I've been texting recently; he often initiates, he'll say good morning/goodnight, send random thoughts throughout the day, etc. Every time we sit down together on campus, though, it is so hard to talk with him. I try not to overthink it, since I know he's exhausted from an early class by the time I get there, and him still seemingly open to written communication shows some interest... I'm just a little confused. I end up trying and trying, asking questions, but I can only do so much before I myself get uncomfortable and blank.Do you think he's really just tired? He still says we need to hangout, and that he likes texting me... I just wish the in-person stuff was without stress.