How Do You Reply to Deadend Text?

Changing the subtopic like that makes me feel nosey, and the conversation starts to feel one sided. (His answers aren't super short, but no prodding of any kind.)

I'll try sub topic changing next time I hit this wall, and see how it goes. If it starts to feel one sided, I'll try for an exit. "You sound busy, ttyl" or something.

Thanks guys.